课件26张PPT。Unit 12
Life is full of the unexpected.Section A
(1a-2d)unexpected adj. 出乎意料的；始料未及的
by the time 在……以前
backpack n. 背包；旅行包
oversleep v. 睡过头；睡得太久
ring adj. （钟、铃等）鸣；响
give……a lift 捎……一程Words and expressions Do you remember any unexpected situation in your daily life?Warming Upunexpected
eventsreceive the birthday presentbe late for schoolthe shower was used by someone when you want to use itthe buslost the keyleft the schoolbag at homeWhat do you think of the people in these pictures?Look at the pictures. What happened to the girl?1aTell a storyShe got up late. She overslept.By the time she got up, someone had already gotten in the bathroom. She rushed out the door. The bus had left before she got to the station. When she got to school, she realized she had left her backpack at home. …. Listen to Mary talking about her morning. Complete the sentences.1b1. By the time I got up, my brother _____ already _______ in the shower.
2. By the time I got outside, the bus _____ already ______.
3. When I got to school, I realized I _____ ______ my
backpack at home.hadgottenhadlefthadleftTake turns being Mary. Look at the pictures and talk about what happened this morning. 1cWhat happened?I overslept. By the time I got up, my brother had already gotten in the shower.Oh, what a pain!Oh, what a pain!So, after he out of the shower, I took a quick shower and got dressed. But by the time I went outside, the bus had already left.Oh, what a pain!Oh, no!Oh, yes! So I ran all the way to school. But when I got to school, I realized I had left my backpack at home. No wonder you
look stressed.Listen to Mary continue her story. Number the pictures [1-4] in the correct order.2a3124Fill in the blanks with the correct forms of the verbs in brackets. Then listen again and check your answers.2b1. When I _______ (get) home, I realized I ________ (leave) my keys in the backpack.
2. By the time I _____ (get) back to school, the bell _________ (ring).
3. By the time I _______ (walk) into class, the teacher __________ (start) teaching already.gothad leftgothad rungwalkedhad startedMake up an ending for the story and share it with your partner. 2cThink about various endings and share them with your partner. The teacher looked at Mary and asked her if she had finished the homework. Mary told her the unexpected things she met with this morning but they sound like excuses to the teacher. Therefore, Mary was asked to finish the homework in the class. What an unforgettable day it is for Mary!Role-play the conversation.2dWhy were you late for class today, Kevin?My alarm clock didn’t go off! I kept sleeping, and when I woke up it was already 8:00 a.m.!Oh, no!So I just quickly put on some clothes and rushed out of the door.You didn’t eat breakfast?No, I didn’t even brush my teeth or wash my face! But before I got to the bus stop, the bus had already left.Then how did you get here?Luckily, Carl’s dad saw me on the street and gave me a lift in his car.Well, at least by the time you got to school, you were only five minutes late for class. Language points2. Life is full of the unexpected.
unexpected adj. 出乎意料的；始料不及的
e.g. It will not be unexpected if Tom comes late again, because he is always like this. 如果汤姆又迟到了, 一点也不意外, 因为他一向如此。1. oversleep (overslept, overslept) v. 睡过头；睡得太久
e.g. Don’t oversleep, Mary! You are to be late. 玛丽，别睡过头了！你要迟到了。2. By the time I got up, my brother had already gotten in the shower.
by the time 在……以前, 常引导表示过去的时间状语从句, 主句常用过去完成时, 即“had+动词过去分词”。
e.g. By the time I got there, he had already left. 在我到那儿之前, 他已经离开了。3. So I just quickly put on some clothes and rushed out of the door.
rush out of 冲出去，冲出……
例句：
Henry rushed out of the room and disappeared in the rain. 亨利
出房间，消失在了雨中。4. Luckily, Carl’s dad saw me on the street and gave me a lift in his car.
gave…a lift 捎……一程
e.g. Could you give me a lift, please? 请问你能否捎我一程？
e.g. Jim gave me a lift on my way home yesterday.吉姆昨天在我回家的路上捎了我一程。根据句意和汉语提示，填写单词。
1. There will be an __________ (意外的) surprise.
2. The children _________ (冲，奔) out the school when the bell rang.
3. Yesterday the girl ________ (违反) the rule and her teacher was angry.
4. When I was about to read my book, I found I ________ (忘了带) it at home.即学即练unexpectedrushedbrokehad leftThanks!课件33张PPT。Unit 12
Life is full of the unexpected.Section A
(3a-4c)What do you know about these pictures?How about these pictures?Read the passage and answer the questions.3a1. Which two events does the writer mention?The writer mentions the September 11 attack in New York and
the earthquake in New Zealand.2. How did the writer end up missing both events?The writer went to get a coffee first and was not in the office when the plane hit the World Trade Center. He/she had overslept and missed his/her flight, so he/she was able to avoid the earthquake. Life Is Full of the Unexpected
In May 2001, I found a job in New York at the World Trade Center. On September 11, 2001, I arrived at my building at around 8:30 a.m. I was about to go up when I decided to get a coffee first. I went to my favorite coffee place even though it was two blocks east from my office. As I was waiting in line with other office workers, I heard a loud sound. Before I could join the others outside to see what was going on, the first plane had already hit my office building. We stared in disbelief at the black smoke rising above the burning building. I felt lucky to be alive. Almost 10 years later, I woke up at 10:00 a.m. on February 21, 2011 and realized that my alarm had never gone off. I jumped out of bed and went straight to the airport. But by the time I got to the airport, my plane to New Zealand had already taken off. “This is the first holiday I've taken in a year, and now I've missed my plane. What bad luck!” I thought to myself. The other planes were full so I had to wait till the next day. The next morning, I heard about the earthquake in New Zealand the day before. My bad luck had unexpectedly turned into a good thing.Find words from the passage with opposite meanings to the words below.3b1. lost:
2. west:
3. below:
4. dead:
5. empty:foundeastabovealivefull1. I found the money on the floor.
2. The sun rises in the east.
3. There was a large bird flying above us.
4. His family was so happy to hear he was still alive.
5. The train was so full that I couldn’t get on the
train at all.Retell one of the events to your partner. Use these words and phrases to help you.3cStare in disbelief take off unexpected, burn above alive till/until
arrive at be about to even thoughe.g. On September 11, 2001, I arrived at my...Language points1. I was about to go up when I decided to get a coffee first.
be about to 意为“忙于；即将做某事”。侧重于表示
作马上就要发生，常与when引导的从句连用，但不与
体的时间状语连用。
e.g. One of my friends is about to have her second baby. 我的一个朋友马上就要生第二个小孩了。2. I went to my favorite coffee place even though it was two
blocks east from my office.
（1）even though 意为“即使， 虽然， 尽管”， 用于引导
让步状语从句。
e.g. His?mind?was?clear?even?though?he?was?very?ill.?尽管病得厉
害，但他头脑仍很清楚。
（2）block 名词，意为“街区”。
e.g. He’s the best teacher, even though he has the least experience. 他虽然经验最少，却是最好的老师。3. We stared in disbelief at the black smoke rising above the burning building.
（1）stare 动词，意为“盯着看， 凝视”。表示看得比较仔细，有时候也带有吃惊的意味去看，常与at、into连用。
e.g. Don’t stare at me like that. 别那样盯着我看。（2）in disbelief 意为“不相信 ，疑惑， 怀疑”。
e.g. Tamara stared at him in disbelief, shaking her head.
塔玛拉一边狐疑地盯着他看，一边摇着头。
e.g. She looked at him in disbelief. 她全然不信地看着他。 （3）above 介词，意为“在……正上方；高于”，表示位置，与 below相对。
e.g. That big high-rise above us is where Brian lives. 我们上面的那座摩天大楼就是布赖恩住的地方。
e.g. He lifted his hands above his head. 他将双手举过头顶。① above作介词，还可表示在地位、级别、能力、资历、重要性等方面“超过，在……之上，比……强”。
e.g. He is above the others in ability. 他的能力优于其他人。
e.g. He is above me in every way. 他各个方面都比我强。【拓展】② above还可作副词，意为“在上面”。 e.g. There are snowy peaks above.上面是白雪皑皑的群峰。
e.g. See the examples given above. 见上述例子。（4）burn 动词，意为“着火，燃烧”。其过去式和过去分词分别为burnt、burnt或burned、burned。
e.g. Ouch! The sand is so hot! It can burn my feet.?哎哟！沙子这么烫！会烫伤脚的。
burning 形容词，意为“着火的；燃烧的”。
e.g. He was trapped in a burning house.?他被困在正在燃烧的房屋里。【拓展】4. I felt lucky to be alive.
alive 意为“活(着)的；在世的；(继续)存在的”，一般作表语；也可以作后置定语或宾补。 反义词是dead。
e.g. Do you know she’s alive? 你知道她还活着吗？
e.g. People alive should try their best to live better. (后置定语)活下来的人应该尽力生活得更好。
e.g. Tom was kept alive in the big fire. (宾补) 汤姆在这次大火中活下来了。5. But by the time I got to the airport, my plane to New Zealand had already taken off.
take off 意为“脱掉； 起飞”。
e.g. He took off his hat and bowed as he passed. 他经过时脱帽鞠躬。
e.g. We eventually took off at 11 o’clock and arrived in Venice at 1:30. 我们终于在11点起飞，1:30 到达威尼斯。Grammar Focus语法聚焦过去完成时一、定义
过去完成时表示一个动作或状态在过去某一时间或动作之前已经
完成或结束, 也可能是早已完成或结束, 即“过去的过去”；也可
指过去的动作延续到过去的某个时刻。
二、结构
“had +动词的过去分词”三、用法 表示过去某一时间或动作之前已经发生或完成的动作或存在的状态。句中常用by、before、when、until等词引导时间状语。 它是以过去某一时间为起点, 所以过去完成 时是一个相对的时态, 表示的是“过去的过去”。只有和过去某时间或某动作相比较时才能用到它。
e.g. Most of the guests had left when he arrived at the party.
当他到达晚会时, 他发现大多数客人已经离开了。 2. 过去完成时还可表示过去某一时刻之前 发生的动作或状态持
续到过去某个时间或持续下去, 常与for、since等词连用。
e.g. When Jack arrived, Mary had been away for almost an hour.
当杰克到时, 玛丽已经离开快一个小时了。 三、句式 【易混辨析】1. 过去完成时与一般过去时的区别 一般过去时表示过去时间内发生的动作或存在的状态；过去完成时主要体现过去发生的两个动作先后有别，即比过去发生的某动作还要“过去”，两个动作中先发生的是过去完成时，后发生的则只用一般过去时。
e.g. She lived in New York.她住在纽约。
e.g. She had lived in New York for 8 years before she came to China.她在来中国之前已经在纽约住了8年。2. 过去完成时与现在完成时的区别现在完成时强调对现在的影响或结果；而过去完成时强调对过去的影响或结果。
e.g. I have been to Beijing twice. (到现在为止)我去过北京两次。
e.g. I had been to Beijing twice by the end of last year. 到去年年底，我已经去过北京两次了。3. 时态的判定(1) 主句为一般过去时,宾语从句中的动作表示已完成时常用过去完成时。
e.g. Amy told me that she had worked in the hospital for 5 years.埃米告诉我，她已经在那家医院工作5年了。
e.g. He told me that he had told Mary about the meeting already.他告诉我，他已经把有关会议的事情告诉了玛丽。
(2) 在有when、before、after等引导的状语从句的句子中，先发生的动作常用过去完成时，后发生的动作用一般过去时。
e.g. When I got home, my mother had finished cooking.我到家时，妈妈已经做好饭了。
e.g. Mother had already cooked dinner before I returned home.在我回家前，妈妈已经做好饭了。
e.g. My watch went well after I'd had it repaired.我的手表修了以后，走得很准。
(3) 有时句子中没有明显的时间状语，动作发生的时间先后需根据上下文判断。
e.g. Her whole family were pleased with her. She had just won the first place in the game.她的全家人为她感到高兴，因为她刚在比赛中获得了第一名。?用所给词的适当形式填空。?
1.?When?I?got?there?the?bus?_________?(go).?
2.?By?the?time?I?got?to?class, ?the?teacher ?__________(start)?teaching.?
3.?We?____________?(learn)?over?1, 000?words?by the
end?of?last?term.
4.?I?___________?(clean)?the?room?before?he arrived?here.?实战演练had gonehad startedhad learnthad cleanedMake sentences using by the time or before.4a1. Tim went into the bathroom.
Mary got up.
By the time Mary got up, Tim had already gone into the bathroom.
2. The coffee became cold.
I put cream (n. 奶油) in the coffee.
Before I put cream in the coffee, the coffee had become cold.3. The teacher collected the math homework. I got to school.
4. I completed the work for my boss. The workday (n. 工作日) ended.
By the time I got to school, the teacher had collected the math homework.I had completed the work for my boss before the workday ended.5. The movie started. I arrived at the cinema.
6. My mother finished making the apple pie (n. 果馅派). I got home from my language course.The movie had started, before I arrived at the cinema.By the time I got home from my language course, my mother had finished making the apple pie.Fill in the blanks with the correct forms of the words in the box.4brush out forget arrive at
go into show up find outBy the time I arrived at the party, everyone else_______ already _________ .
2.When he put the noodles into a bowl, he realized he _____________to add the green beans.
3. By the time my mother came back from the market, I ____already__________ of the door to go to my piano lesson.
hadshown uphad forgottenrushed outhad 4. Before she got to the airport, she _____________ about the earthquake.
5. When she __________ the movie theater, she remembered she had forgotten to feed her dog.
6. Before she got a chance to say goodbye, he ____________ the building.had forgottenarrived athad gone intoWrite two true statements and one false statement about your day yesterday. Then ask your classmates to guess the false statement.4cBy the time I left for school in the morning, _____________________________________.
By the end of the school day, ________________________________.
By dinner time, I _____________________.I saw my teacher clean the classroomI missed my schoolmates so muchate a fish 根据汉语提示写出下面句中所缺的单词。1.?I?got?up?early?this?morning?because?I?didn’t?want?to?_______?(错过)?the?early?bus.??
2.?The?drop?in?prices?was?quiet?___________ (出乎意料的).?
3.?The?______?(工人)?fell?down?and?got?hurt.
4.?The?plane?was?flying?_____?(在上面) the clouds.?
?5.?The?river?goes?through?the?city?from?______? (西)?to?east.missunexpectedworkerabovewest即学即练根据汉语意思完成句子。
1. 我在动物园里见过活鳄鱼。
I have seen a _____?crocodile in the zoo.
2. 他是那场火灾中唯一活下来的人。
He is the only person ____?in the fire.
3. 露西是个活泼的孩子, 大家都喜欢她。
Lucy is a _____?child and everyone likes her.living?alivelivelyReview the content in Grammar Focus. Try to make sentences with before, by the time and be doing…when, and make use of the past perfect tense.
课后作业Thanks!课件34张PPT。Section B
(1a-Self Check)Unit 12
Life is full of the unexpected.It is celebrated every year on the first day of April. It has been popular since the 19th century. The day is not a national holiday?in any country, but it is well known in Europe, Australia, Brazil and the United States.
On this day, people play?jokes?and?
hoaxes on each other. The jokes and their victims are known as "April fools". Hoax stories may be reported by
the press and other media on this day and?explained later.Words and expressions fool n. 愚人；傻瓜
v. 愚弄
costume n. （特定场合穿的）服
装；装束
costume party 化妆舞会
embarrassed adj. 窘迫的；害羞的Put these words in the correct columns in the chart. 1afool invite costume embarrassed go off call get dressed empty show up realize change clock
tired stay upTell your partner about something that happened to you recently. Use two or more words in 1a. 1bLast Friday night, my friend invited me to his birthday party…April Fool's DayWhat did you do on Last April Fool’s Day?Dave, Nick and Joe are talking about April Fool’s Day. Listen and write each person’s name under the correct picture.1cDave Nick Joe Listen again. Who says each of the phrases below? Write D for Dave, N for Nick and J for Joe.1d1. ______ a costume party
2. ______ my alarm went off
3. ______ stayed up all night
4. ______ was tired
5. ______ was really embarrassed
6. ______ the other kids showed up DNJJDNTell April Fool’s Day stories in your group. Use the information in 1c and 1d.1eWhat happened to Dave
on April Fool’s Day?Well, a friend invited him
to a costume party…Have you ever played jokes on others, especially on Aril Fool’s Day? Have you ever been fooled by others? Tell your story to your partner.2aRead the passage quickly. Then match each paragraph with the main idea.2aParagraph 1 One of the most famous tricks
played
Paragraph 2 Examples of funny stories that
happened on April Fool’s Day
Paragraph 3 An introduction to April
Fool’s Day
Paragraph 4 A sad story that happened on
April Fool’s DayUSING BACKGROUND KNOWLEDGE
Carefully reading the first sentence in each paragraph can activate your own knowledge of the topic and help you guess what the whole text is about. April Fool’s Day is a celebration that takes place in different countries around the world. It happens on April 1st every year
and is a day when many people play all kinds of tricks and jokes on each other.
One April Fool’s Day, a reporter in England announced that there would be no more spaghetti because the spaghetti farmers in Italy had stopped growing spaghetti. Many people ran to their local supermarkets to buy as much spaghetti as they could. By the time people realized that the story was a hoax, all of the spaghetti across the country had been sold out. In another famous trick a TV show in England reported the discovery of special water. They said this water would help people lose weight and that one customer had already lost a lot of weight in just four months. By the end of the day, more than 10,000 people had phoned the TV station to find out how to get this water.
Many April Fool’s jokes may end up being not very funny. A famous TV star once invited his girlfriend onto his show on April Fool’s Day. He asked her to marry him. The lady was so happy because she really wanted to get married. However, when she said “yes”, he replied, “April Fool!” That little joke didn’t have a very happy ending. The TV star lost his girlfriend and his show was canceled.
One of the world’s most famous tricks, however, happened in October rather than in April. In that month in 1938, actor Orson Welles announced on his radio program that aliens from Mars had landed on the earth. He described where they had landed and told how they were moving across the United States. Welles made it sound so real that hundreds of people believed the story, and fear spread across the whole country. By the time police officers announced that the story was a hoax, thousands of people had left their homes.
1. fool n. 傻瓜；愚人；受骗者
常用短语：make a fool of... 取笑；捉弄
复数形式：fools
e.g. Don't be a fool！别这么傻了！
fool vt. 愚弄，欺骗；
e.g. He was fooled by his friend on April Fool’s Day.
愚人节那天他被他的朋友愚弄了。Language points【拓展】2. embarrassed adj. 局促不安的；为难的；尴尬的；窘迫的
e.g. He looked a bit embarrassed. 他看起来有点尴尬。
embarrassing adj. 使人尴尬的，令人为难的
e.g. That was an embarrassing situation for me. 那种情形让我难堪。【拓展】3. get dressed 穿上衣服
相当于be dressed或dress up。如果后面又表示衣服颜色的名
词作宾语时，需要用介词in。
e.g. The little girl went to the bedroom to get dressed. 小女孩走进卧室打扮起来。
e.g. My mother is dressed in red. 我妈妈穿着红色的衣服。4.?April?Fool’s?Day?is?a?celebration?that?takes place?in?different?
countries?around the?world. 愚人节是一种发生在世界各国的
庆祝活动。
take place 意为“发生；进行；举行；产生”。
【辨析】e.g. The?sports?meeting?will?take?place?in our?school.?运动会将在我校举行。
e.g. I?happened?to?be?in?the?lab?that?day.?那天我碰巧在实验室。5. It happens on April 1st every year and is a day when many people play all kinds of tricks and jokes on each other. 愚人节是每年的四月一日，在这一天，人们互相捉弄开各种玩笑。
play tricks on sb. 意为“捉弄某人”，而play jokes on sb.则是“对某人开玩笑 ”的意思。
6.?Many?people?ran?to?their?local?supermarkets?to?buy?as?much?
spaghetti?as?they?could.?很多人跑到当地的超市抢购尽可能多的意大利面条。
“as?+形容词/副词的原级+?as?sb.?can?/?could?”相当于“as?+?形容词/副词原级+?as?possible”，意为“尽可能地……”，在句中作状语。?
e.g. ?We?must?do?everything?as?well as we?can.?
( =?We?must?do?everything?as?well?as?possible.?)
我们要尽量做好每一件事。7. He asked her to marry him. 他向她求婚。
marry sb. 意为“嫁/娶某人”。
get married to sb. 意为“嫁/娶某人;与某人结婚”，为短暂性词组。
be married to sb. 意为“嫁/娶某人；与某人结婚”，是延续性词组。
e.g. She married John last year.
(= She got married to John last year.)
(= She has been married to John for one year.)
她去年嫁给了John。Read the passage carefully and answer these questions. 2c1. Why did the supermarkets run out of spaghetti one April Fool’s Day? A reporter announced that there would be no more spaghetti as spaghetti farmers in Italy had stopped growing spaghetti.2. What did the TV show say the special water could do?
3. Why did the TV star’s joke have a bad ending?
4. When did Orson Welles tell people about aliens from Mars landing on the earth?
It was said that the special water would help people lose weight.He lost both his girlfriend and his show.It was in October 1938.
5. Why did so many people believe Orson Welles?
Orson Welles made it sound so real that hundreds of people believed the story.6. Which of these stories is the most believable? Which is the least believable? Why?
I think the story of a famous movie star is the most believable. The story of aliens from Mars is the least believable. Because the movie star is living with people. People never see any aliens on the earth. 7. Would you be fooled by any of these stories?
I think the story that there would be no more spaghetti because the spaghetti farmers in Italy had stopped growing spaghetti is the most unbelievable. Because farmers in Italy would never stop growing spaghetti.Fill in the blanks with the correct forms of the verbs in brackets.2d1. After the spaghetti story __________ (appear) in the news, everyone _______ (rush) to the supermarkets.
2. By the time people ________ (find out) the story was not true, all
the spaghetti in the supermarkets _______________ (disappear).appeared rushed found out had disappeared 3. By the time the day ______ (end), more than 10,000 people _________ (call) the TV station to ask about the special water.
4. By the time the show _____ (end), the TV star ________ (lose) his girl friend.
5. By the time police officers ____ (tell) the country that the story was a hoax, many people ____________ (run away) from their homes. ended had called endedhad lost told had run awayTell your funny story from 2a to the class. The class will vote for: 2ea. the funniest joke
b. the most embarrassing joke
c. the most creative joke A: What’s your story?
B: Well, last year, on the first day of school, my sister put a piece of paper on my back that said “Please say hello.” All
morning at school...Can you remember a lucky or an unlucky day? What happened? Make some notes about what you remember.3aWrite a story about your lucky or unlucky day and tell your story to a partner or the class.3b My lucky/unlucky day
I will always remember the date…
This was the luckiest/unluckiest day of my life…
When I woke up that morning…
Later that day,…
I couldn’t believe…
Then/After that, …
Finally,…
I think…
What a lucky/an unlucky day!Complete the passage with the correct form of the words in the box.1Self Checkcancel miss west accident
lady officer market unexpected Last Saturday after my French course, I decided to drive to the ________ to buy a meat pie for dinner. As I was heading ________, I saw a huge truck in the middle of the road. There had been a(n) ________ and there were many police ________ around. I turned around and decided to go to a nearby mall. However, I ________ the road that led to the mall. Then I saw a restaurant that sold chicken noodles. I went inside and the ________, who was the owner, served me the most delicious bowl of chicken noodles ever. I had made a(n) ________ discovery! I'm so glad that I ________ my plan to go to the market.marketwestaccidentofficersmissedladyunexpectedcanceledThink of ways to finish the answers.21. A: Why didn't you hand in your science homework?
B: Before I could start working on it, __________.
2. A: Why didn't you take a shower this morning?
B: By the time I got up, _________.
3. A: Why did you have to walk home from school?
B: By the time I left my school, _________.根据汉语意思完成下面的句子。
?1.?人们相互开各种各样的玩笑。????
People?______?all?kinds?of?_____?_____?each
?other.?
?2.?她父亲抚养她直到她结婚。
? Her?father?supported?her?until?she?_____?________.?
?3.?一架飞机将降落在机场。???
? A?plane?will?______?______?the?airport.??
playjokes with gotmarried land on即学即练4. 生日晚会什么时候举行？
When?will?the?birthday?party?______?______??
5.?这个小男孩想要尽可能多的礼物。?
The?little?boy?wants?_____?_____?_______?____?
possible.??
6.?我下个月底会回来。??
?I?will?be?back?_____?_____?_____?_____?next
?month.?? take place as many presents asby the end of7.?这家商店的衬衫都卖光了。???
The?shop?_____?_____?all?their?shirts.??
8.?我穿好衣服吃早餐。???
I?___?_______?and?had?breakfast?
9. 你觉得这里的食物怎么样？
_____?do?you?_____?_____?the?food?here??
10. 当他问到我这个问题时我恰好读过这篇文章。
I?________?to?have?read?the?article?when?he
? asked?me?about?it.?sold outgot dressedHowfeel abouthappenedReview the Past perfect tense.
课后作业Thanks!
