人教版八年级英语下册单元课时练
Unit 6 An old man tried to move the mountains.
Section A(1a-2d)
一、根据句意及汉语提示填写单词。
1. These old pictures often __________ (提醒) me of my days in junior school.
2. She picked up the __________ (石头) and threw them away into the river.
3. The old woman looks __________ (虚弱的) and poor.
4. 一I think it’s __________ (愚蠢的) to play computer games until midnight.
—I agree with you.
5. Don’t __________ (射击) the bird. It’s not good to do that.
二、单项填空。
1. —Look! Who's __________ old man over there
—Oh, he's my neighbor. He's __________ excellent volunteer, though he's 86.
A. a; an B. the; an C. the; a D. a; a
2. He will go to the park as soon as his homework __________.
A. will do B. did C. doing D. is done
3. I like these photos because they can __________ me __________ my hometown.
A. think; of B. remind; of C. wake; up D. look; up
4. Study is very important for us, so we should study hard __________ playing computer games every day.
A. instead of B. instead C. rather than D. because of
5. —What smells terrible, Tom
—Oh, sorry, I will __________ my shoes right away.
A. get away B. look away C. put away D. take away
6. —May I go to Sunwen Park with you this Saturday
— No, you can't. __________you have a ticket. I only have one ticket,
A. Unless B. As soon as C. Until D. If
7. My mother always tells me __________on the street, because it is very dangerous.
A. to play B. playing C. not to play D. not playing
8. 1 asked two people the way to the museum, but __________ of them knew. Because they were new here, too.
A. neither B. either C. both D. also
9. This story was so __________ that the man cried for many times.
A. move B. moved C. moving D. moves
10. —Would you mind my sitting here
—__________. It is for an old man.
A. Yes, go ahead B. Yes, you can't
C. Better not D. Of course not
三、根据汉语意思完成句子。
1. 他努力争取考试及格, 但是失败了。
He _________________ the exam, but he failed.
2. 我——有空就过来看你。
I will come to see you _________________free.
3. 不同的人对这部电影有不同的看法。
Different people have _________________ this movie.
4. 在30岁时, 他戒烟了。
_________________30 years old, he _________________.
5. 上个月他派我去北京参加了一个会议。
He _________________ attend a meeting in Beijing last month.
四、阅读理解。
Dongchang Square Lu Han is a famous singer and actor. He has millions of fans all over the country. Would you like to see him Come on! Place: Dongchang Square Time: 6:00 pm, June 7th Ticket: $ 80
Sun Club Would you like to be an artist If you want, our Sun Club will help you become an art it with the help of our professional coaches. Just come and have a try! Music lesson price; $7 Dance lesson price: $ 5 Painting lesson price; $ 8
Yunhe Museum You may find your way around with the help of the floor plan. If you come here with your children, keep close to them, please. The museum is very big and it is easy to get lost. Open:9 :00 am- 12:00 am; 2:30 pm-5:30 pm Admission: $ 1(Free: children under 6 years old)
Half-price Movie Tickets Buy a full-price movie ticket on Tuesdays or Wednesdays, and you can get a second ticket for a friend at only half price. The latest movies are all here.
1. You can see Lu Han _________.
A. on Dongchang Square B. at the cinema
B. in Sun Club D. in Yunhe Museum
2. People can't visit Yunhe Museum at _________ every day.
A. 10:00 am B. 3:00 pm C. 4:00 pm D. 8:00 pm
3. __________ can get into Yunhe Museum for free.
A. An adult B. A student C. A teacher D. A child under 6 years old
4. If Tom pays 16 dollars for a full-price movie ticket on Tuesday, the price of the second ticket is _________.
A. 5 dollars B. 8 dollars C. 15 dollars D. 32 dollars
5. You can read this passage from a (an) _________.
A. science book B. storybook C. ad(广告) D. letter
五、短文填空根据课本Section A 2d改编)。
请用适当的词完成下面的短文, 每个空只能填写一个形式正确、意义相符的单词。
Wang Ming thinks that the story of Yu Gong is really 1. _________. Yu Gong found a good way to 2. _________ his problem, Yu Gong kept 3. _________ to move a mountain and didn't give 4. _________. The story tried to show us that 5. _________is possible if you work hard. But Claudia thinks it is a little bit 6. _________. He thinks we should find other 7. _________to solve the problem. For example, he thinks Yu Gong could 8. _________ a road. The teacher said 9. _________ of them are wrong. There are many 10. _________ to a story and many ways to understand it.
Section A(3a-3c)
一、根据句意及汉语提示写单词。
1. Don’t touch the __________ (尾巴) of dogs. It’s dangerous.
2. The child __________ (隐蔽) himself behind a tree so that the others couldn’t find him.
3. The Chinese medicine and Chinese characters (汉字) are so __________ (神奇的).
4. Some people like to learn by using their hands to touch __________ (物体) in the museum.
5. On the way to the top of the mountain, many tourists were so tired that they had to walk with __________ (棍子).
二、单项填空。
1. Don't worry. He is _________ to take care of the little baby.
A. careful enough B. carefully enough
C. enough careful D. enough carefully
2. Lucy _________ on the street. She didn't find her way.
A. gets lost B. lost C. got lost D. is lost
3. We all believe that he _________ work out the problems in three days.
A. will able to B. will be able to C. was able to D. is able to
4. As soon as the books _________, they are sold out in a week.
A. come across B. come along C. come on D. come out
5. I won't go to the meeting _________ I' m invited.
A. but B. if C. unless D. when
6. He has to work hard to make a lot of money _________ he can afford his children' s education.
A. so that B. such that C. in order to D. so as to
7. The nurse won't leave her patients _________ she's sure they are all taken good care of.
A. unless B. because C. since D. if
8. —Have you ever seen the American movie _________ Mission: Impossible-Fallout
—Yes, it is fantastic.
A. calls B. calling C. called D. call
9. The story was so funny that I couldn't stop _________.
A. laughing B. to laugh C. laugh D. laughed
10. —Do you know _________
— Let me see. I remember it was on March 18th.
A. why did they move here B. why they moved here
C. when did they move here D. when they moved here
三、根据汉语意思完成句子。
1. 在我五岁的时候, 我就对游泳感兴趣。
When I was 5 years old, I _______________________________.
2. 井柏然是电影《捉妖记》的主角。
Jin Boran is _______________________________ in the movie— The Monster.
3. 我们大部分人都第一次听到这个故事。
Most of us hear the story _______________________________.
4. 你能告诉我如何把冰变成水吗
Can you tell me how to _______________________________
5. 《西游记》在中国是最受欢迎的故事之一。
Journey to the West is _______________________________ in China.
四、阅读理解。
I know I'm not an ordinary(平常的) ten-year-old kid, I do ordinary things. I eat ice-cream, ride my bike and play football. Things like that makes me ordinary. But I know ordinary kids don't make other ordinary kids run away screaming(尖叫). I know ordinary kids don't get stared at(被盯着看) where they go.
If I can do magic, I have only one wish. I want to have a normal face no one ever noticed. But I'm used to how I look. I know how to pretend I don't see people's strange facial expressions(面部表情). Mom, Dad and I have gotten pretty good at that kind of thing, but Via is not good at it. She gets really angry when people do something bad. For example, one time some older kids made some noises(噪音). I don't know what the noises were about because I didn't hear them, but Via heard and she started shouting at them. That's the way she is.
Via doesn't see me as ordinary. She says if she does, she doesn't need to look after me so much. Mom and Dad don't see me as ordinary, either. They see me as extraordinary(非凡的). I think the only person realizing how ordinary I am is myself.
My name is August. 1 won't describe what I look like. Whatever you're thinking, it's probably worse.
1. What doesn't the writer think a ten-year-old kid do normally
A. Eat ice-cream. B. Ride bikes. C. Get stared at. D. Play football.
2. What does the underlined word “pretend" mean in Chinese
A. 想象 B. 假装 C. 感受 D. 看待
3. According to the passage, who sees the writer as an ordinary kid
A. His father. B. His mother. C. Via. D. Himself.
4. From the passage, we can know that Via _________.
A. is good at shouting
B. doesn't get angry when the writer was laughed at
C. is the writer's friend
D. always takes care of the writer
5. What CANNOT we infer from the passage
A. The writer can do some great magic.
B. The writer gets used to how he looks.
C. The writer isn't probably good looking.
D. The writer' s family love him very much.
五、短文填空(根据课本Section A 3a改编)。
请用适当的词完成下面的短文, 每个空只能填写一个形式正确、意义相符的单词。
Pupils in England were able to watch a new TV program in November 1979. It is 1.__________Monkey. However, this story is not new to Chinese children. The Monkey King is the main 2.__________. The Monkey King can 3.__________ 72 changes to his shape and size, turn himself 4.__________ different animals and objects. But unless he can 5.__________ his tail, he can't turn himself into a man. He uses a 6.__________stick to fight with bad people. He is 7.__________able to make the stick small, big and long. The Monkey King has excited the Chinese children 8.__________ years. Western children became 9. .__________ in this story as soon as the TV 10.__________ came out more than thirty years ago.
Section A(Grammar Focus-4c)
一、根据句意及首母提示填写单词。
1. The yellow shirt doesn’t f__________ me. It’s too large.
2. Tom and Alice got m__________ three years ago and they have a lovely baby now.
3. Once u__________ a time, there was a tiger in the mountain.
4. The old c__________ are very happy because their son will return from Canada.
5. Mr. Brown looks very kind because he always s__________ when he is talking to others.
二、根据汉语意思完成句子,每空一词。
1.他昨天一离开家就给我打了电话。
He called me __________ __________ __________ he left home yesterday.
2.她太忙了以至于没空做晚餐。
She was __________ busy __________ she had no time to cook dinner.
3.马克会来参加聚会的,除非他生病不能来。
Mark __________ come to the party, __________ he is ill and can’t come here.
4.你最好随身带着地图,以免迷路。
You’d better take the map with you __________ __________ you can’t get lost.
三、单项选择
1.She stopped talking __________ her mother came into the room.
A. as soon as B. unless
C. though
2.Lots of people exercise every morning __________ bad weather stops them.
A. if B. unless
C. until D. since
3.一Harry Potter is __________ an interesting novel __________ I want to read it again.
—I agree with you.
A. so; that B. too; to
C. such; that D. as; as
4.When you are in your school dining hall during lunchtime, you may feel lonely __________ you can find someone to have lunch with.
A. if B. unless
C. after D. because
5.Jack’s mother was so tired. She fell asleep __________ she lay down on the bed.
A. until B. as soon as
C. unless D. although
四、完形填空。
A young man saw a gold coin shining in the water when he walked by the lake. It 1 him and he jumped into the water to look for it, but he couldn’t reach it no matter how hard he tried. Being wet and tired, he had to have a 2 . After the water became calm, the gold coin 3 again.
He jumped into the water again, 4 he got nothing. Then he did it again and again. However, he couldn’t get the object in the 5 .
His father came to look for him. Seeing his son’s action, he asked 6 , “What made your body wet ” The young man answered, “I’m sorry, Dad. I found a gold coin in the water just now, but I can’t get 7 anyway.”
The father watched the tree near the lake and 8 his son, “Look! It’s not a gold coin, but the reflection (倒影) of a piece of metal 9 the tree.”
In our life, we shouldn’t make such a (n) 10 mistake like this. We should have a clear mind and be thankful for what we have and work hard to look for the real “coin”.
( )1. A. worried B. relaxed C. risked D. excited
( )2. A. rest B. look C. coin D. help
( )3. A. dropped B. shone C. changed D. lost
( )4. A. but B. so C. or D. because
( )5. A. boat B. water C. sand D. road
( )6. A. angrily B. excitedly C. happily D. kindly
( )7. A. one B. this C. that D. it
( )8. A. reminded B. understood C. beat D. asked
( )9. A. on B. for C. in D. with
( )10. A. perfect B. silly C. smart D. exciting
人教版八年级英语下册单元课时练
Unit 6 An old man tried to move the mountains.
Section A(1a-2d)
一、根据句意及汉语提示填写单词。
1. These old pictures often __________ (提醒) me of my days in junior school.
2. She picked up the __________ (石头) and threw them away into the river.
3. The old woman looks __________ (虚弱的) and poor.
4. 一I think it’s __________ (愚蠢的) to play computer games until midnight.
—I agree with you.
5. Don’t __________ (射击) the bird. It’s not good to do that.
二、单项填空。
1. —Look! Who's __________ old man over there
—Oh, he's my neighbor. He's __________ excellent volunteer, though he's 86.
A. a; an B. the; an C. the; a D. a; a
2. He will go to the park as soon as his homework __________.
A. will do B. did C. doing D. is done
3. I like these photos because they can __________ me __________ my hometown.
A. think; of B. remind; of C. wake; up D. look; up
4. Study is very important for us, so we should study hard __________ playing computer games every day.
A. instead of B. instead C. rather than D. because of
5. —What smells terrible, Tom
—Oh, sorry, I will __________ my shoes right away.
A. get away B. look away C. put away D. take away
6. —May I go to Sunwen Park with you this Saturday
— No, you can't. __________you have a ticket. I only have one ticket,
A. Unless B. As soon as C. Until D. If
7. My mother always tells me __________on the street, because it is very dangerous.
A. to play B. playing C. not to play D. not playing
8. 1 asked two people the way to the museum, but __________ of them knew. Because they were new here, too.
A. neither B. either C. both D. also
9. This story was so __________ that the man cried for many times.
A. move B. moved C. moving D. moves
10. —Would you mind my sitting here
—__________. It is for an old man.
A. Yes, go ahead B. Yes, you can't
C. Better not D. Of course not
三、根据汉语意思完成句子。
1. 他努力争取考试及格, 但是失败了。
He _________________ the exam, but he failed.
2. 我——有空就过来看你。
I will come to see you _________________free.
3. 不同的人对这部电影有不同的看法。
Different people have _________________ this movie.
4. 在30岁时, 他戒烟了。
_________________30 years old, he _________________.
5. 上个月他派我去北京参加了一个会议。
He _________________ attend a meeting in Beijing last month.
四、阅读理解。
Dongchang Square Lu Han is a famous singer and actor. He has millions of fans all over the country. Would you like to see him Come on! Place: Dongchang Square Time: 6:00 pm, June 7th Ticket: $ 80
Sun Club Would you like to be an artist If you want, our Sun Club will help you become an art it with the help of our professional coaches. Just come and have a try! Music lesson price; $7 Dance lesson price: $ 5 Painting lesson price; $ 8
Yunhe Museum You may find your way around with the help of the floor plan. If you come here with your children, keep close to them, please. The museum is very big and it is easy to get lost. Open:9 :00 am- 12:00 am; 2:30 pm-5:30 pm Admission: $ 1(Free: children under 6 years old)
Half-price Movie Tickets Buy a full-price movie ticket on Tuesdays or Wednesdays, and you can get a second ticket for a friend at only half price. The latest movies are all here.
1. You can see Lu Han _________.
A. on Dongchang Square B. at the cinema
B. in Sun Club D. in Yunhe Museum
2. People can't visit Yunhe Museum at _________ every day.
A. 10:00 am B. 3:00 pm C. 4:00 pm D. 8:00 pm
3. __________ can get into Yunhe Museum for free.
A. An adult B. A student C. A teacher D. A child under 6 years old
4. If Tom pays 16 dollars for a full-price movie ticket on Tuesday, the price of the second ticket is _________.
A. 5 dollars B. 8 dollars C. 15 dollars D. 32 dollars
5. You can read this passage from a (an) _________.
A. science book B. storybook C. ad(广告) D. letter
五、短文填空根据课本Section A 2d改编)。
请用适当的词完成下面的短文, 每个空只能填写一个形式正确、意义相符的单词。
Wang Ming thinks that the story of Yu Gong is really 1. _________. Yu Gong found a good way to 2. _________ his problem, Yu Gong kept 3. _________ to move a mountain and didn't give 4. _________. The story tried to show us that 5. _________is possible if you work hard. But Claudia thinks it is a little bit 6. _________. He thinks we should find other 7. _________to solve the problem. For example, he thinks Yu Gong could 8. _________ a road. The teacher said 9. _________ of them are wrong. There are many 10. _________ to a story and many ways to understand it.
参考答案
一、根据句意及汉语提示填写单词。
1. remind 2. stones 3. weak 4. silly 5. shoot
二、单项填空。
1-5 BDBAD 6-10 ACACC
三、根据汉语意思完成句子。
1.tried to pass
2. as soon as I am
3. different opinions about
4. At the time of/ When he was , gave up smoking.
5.sent me to
四、阅读理解。
1-5 ADDBC
五、短文填空根据课本Section A 2d改编)。
1. interesting. 2. solve 3. trying 4. up. 5. anything 6. silly. 7. ways 8. build 9. neither 10. sides
Section A(3a-3c)
一、根据句意及汉语提示写单词。
1. Don’t touch the __________ (尾巴) of dogs. It’s dangerous.
2. The child __________ (隐蔽) himself behind a tree so that the others couldn’t find him.
3. The Chinese medicine and Chinese characters (汉字) are so __________ (神奇的).
4. Some people like to learn by using their hands to touch __________ (物体) in the museum.
5. On the way to the top of the mountain, many tourists were so tired that they had to walk with __________ (棍子).
二、单项填空。
1. Don't worry. He is _________ to take care of the little baby.
A. careful enough B. carefully enough
C. enough careful D. enough carefully
2. Lucy _________ on the street. She didn't find her way.
A. gets lost B. lost C. got lost D. is lost
3. We all believe that he _________ work out the problems in three days.
A. will able to B. will be able to C. was able to D. is able to
4. As soon as the books _________, they are sold out in a week.
A. come across B. come along C. come on D. come out
5. I won't go to the meeting _________ I' m invited.
A. but B. if C. unless D. when
6. He has to work hard to make a lot of money _________ he can afford his children' s education.
A. so that B. such that C. in order to D. so as to
7. The nurse won't leave her patients _________ she's sure they are all taken good care of.
A. unless B. because C. since D. if
8. —Have you ever seen the American movie _________ Mission: Impossible-Fallout
—Yes, it is fantastic.
A. calls B. calling C. called D. call
9. The story was so funny that I couldn't stop _________.
A. laughing B. to laugh C. laugh D. laughed
10. —Do you know _________
— Let me see. I remember it was on March 18th.
A. why did they move here B. why they moved here
C. when did they move here D. when they moved here
三、根据汉语意思完成句子。
1. 在我五岁的时候, 我就对游泳感兴趣。
When I was 5 years old, I _______________________________.
2. 井柏然是电影《捉妖记》的主角。
Jin Boran is _______________________________ in the movie— The Monster.
3. 我们大部分人都第一次听到这个故事。
Most of us hear the story _______________________________.
4. 你能告诉我如何把冰变成水吗
Can you tell me how to _______________________________
5. 《西游记》在中国是最受欢迎的故事之一。
Journey to the West is _______________________________ in China.
四、阅读理解。
I know I'm not an ordinary(平常的) ten-year-old kid, I do ordinary things. I eat ice-cream, ride my bike and play football. Things like that makes me ordinary. But I know ordinary kids don't make other ordinary kids run away screaming(尖叫). I know ordinary kids don't get stared at(被盯着看) where they go.
If I can do magic, I have only one wish. I want to have a normal face no one ever noticed. But I'm used to how I look. I know how to pretend I don't see people's strange facial expressions(面部表情). Mom, Dad and I have gotten pretty good at that kind of thing, but Via is not good at it. She gets really angry when people do something bad. For example, one time some older kids made some noises(噪音). I don't know what the noises were about because I didn't hear them, but Via heard and she started shouting at them. That's the way she is.
Via doesn't see me as ordinary. She says if she does, she doesn't need to look after me so much. Mom and Dad don't see me as ordinary, either. They see me as extraordinary(非凡的). I think the only person realizing how ordinary I am is myself.
My name is August. 1 won't describe what I look like. Whatever you're thinking, it's probably worse.
1. What doesn't the writer think a ten-year-old kid do normally
A. Eat ice-cream. B. Ride bikes. C. Get stared at. D. Play football.
2. What does the underlined word “pretend" mean in Chinese
A. 想象 B. 假装 C. 感受 D. 看待
3. According to the passage, who sees the writer as an ordinary kid
A. His father. B. His mother. C. Via. D. Himself.
4. From the passage, we can know that Via _________.
A. is good at shouting
B. doesn't get angry when the writer was laughed at
C. is the writer's friend
D. always takes care of the writer
5. What CANNOT we infer from the passage
A. The writer can do some great magic.
B. The writer gets used to how he looks.
C. The writer isn't probably good looking.
D. The writer' s family love him very much.
五、短文填空(根据课本Section A 3a改编)。
请用适当的词完成下面的短文, 每个空只能填写一个形式正确、意义相符的单词。
Pupils in England were able to watch a new TV program in November 1979. It is 1.__________Monkey. However, this story is not new to Chinese children. The Monkey King is the main 2.__________. The Monkey King can 3.__________ 72 changes to his shape and size, turn himself 4.__________ different animals and objects. But unless he can 5.__________ his tail, he can't turn himself into a man. He uses a 6.__________stick to fight with bad people. He is 7.__________able to make the stick small, big and long. The Monkey King has excited the Chinese children 8.__________ years. Western children became 9. .__________ in this story as soon as the TV 10.__________ came out more than thirty years ago.
参考答案
一、根据句意及汉语提示写单词。
1. tails 2. hid 3. magic 4. objects 5. sticks
二、单项填空。
1-10 ACBDC AACAD
三、根据汉语意思完成句子。
1. became/ was interested in swimming.
2. the main character
3. for the first time.
4. turn the ice into water
5. one of the most popular stories
四、阅读理解。
1-5 CBDDA
五、短文填空(根据课本Section A 3a改编)。
1. called 2. character. 3. make 4. into 5. hide
6. magic 7. able 8. many 9. interested 10. program
Section A(Grammar Focus-4c)
一、根据句意及首母提示填写单词。
1. The yellow shirt doesn’t f__________ me. It’s too large.
2. Tom and Alice got m__________ three years ago and they have a lovely baby now.
3. Once u__________ a time, there was a tiger in the mountain.
4. The old c__________ are very happy because their son will return from Canada.
5. Mr. Brown looks very kind because he always s__________ when he is talking to others.
二、根据汉语意思完成句子,每空一词。
1.他昨天一离开家就给我打了电话。
He called me __________ __________ __________ he left home yesterday.
2.她太忙了以至于没空做晚餐。
She was __________ busy __________ she had no time to cook dinner.
3.马克会来参加聚会的,除非他生病不能来。
Mark __________ come to the party, __________ he is ill and can’t come here.
4.你最好随身带着地图,以免迷路。
You’d better take the map with you __________ __________ you can’t get lost.
三、单项选择
1.She stopped talking __________ her mother came into the room.
A. as soon as B. unless
C. though
2.Lots of people exercise every morning __________ bad weather stops them.
A. if B. unless
C. until D. since
3.一Harry Potter is __________ an interesting novel __________ I want to read it again.
—I agree with you.
A. so; that B. too; to
C. such; that D. as; as
4.When you are in your school dining hall during lunchtime, you may feel lonely __________ you can find someone to have lunch with.
A. if B. unless
C. after D. because
5.Jack’s mother was so tired. She fell asleep __________ she lay down on the bed.
A. until B. as soon as
C. unless D. although
四、完形填空。
A young man saw a gold coin shining in the water when he walked by the lake. It 1 him and he jumped into the water to look for it, but he couldn’t reach it no matter how hard he tried. Being wet and tired, he had to have a 2 . After the water became calm, the gold coin 3 again.
He jumped into the water again, 4 he got nothing. Then he did it again and again. However, he couldn’t get the object in the 5 .
His father came to look for him. Seeing his son’s action, he asked 6 , “What made your body wet ” The young man answered, “I’m sorry, Dad. I found a gold coin in the water just now, but I can’t get 7 anyway.”
The father watched the tree near the lake and 8 his son, “Look! It’s not a gold coin, but the reflection (倒影) of a piece of metal 9 the tree.”
In our life, we shouldn’t make such a (n) 10 mistake like this. We should have a clear mind and be thankful for what we have and work hard to look for the real “coin”.
( )1. A. worried B. relaxed C. risked D. excited
( )2. A. rest B. look C. coin D. help
( )3. A. dropped B. shone C. changed D. lost
( )4. A. but B. so C. or D. because
( )5. A. boat B. water C. sand D. road
( )6. A. angrily B. excitedly C. happily D. kindly
( )7. A. one B. this C. that D. it
( )8. A. reminded B. understood C. beat D. asked
( )9. A. on B. for C. in D. with
( )10. A. perfect B. silly C. smart D. exciting
参考答案
一、根据句意及首母提示填写单词。
1. fit 2. married 3. upon 4. couple 5. smiles
二、根据汉语意思完成句子,每空一词。
5. as soon as 7. so; that 8. will; unless 9. so that
三、单项选择
1—5 ABCBB
四、完形填空。
1-5 DABAB 6-10 DDACB