(共22张PPT)
Section
第 3 课 时 (4a~4c)
…………………………………
A
Unit 3 It must belong to Carla.
The skirt must be Lily’s.
It can’t be John’s because he is a boy.
Discuss
John Lily
情 境 导 入
The hair band may be Mary’s because her hair is longer, but it also might be Lucy’s.
Mary Lucy
情 境 导 入
情态动词中的 must、can、could、may、might 都表推测。其中 must 的可能性最大,can/could 次之,
may/might 最小。
Grammer points
新课探究
must 表示推测“可能性”时,意为“一定;准是”,语气较肯定,较有把握。“must+动词原形”表示对现在情况较有把握的推测,意为“一定”;“must have+动词的过去分词”表示对过去情况较有把握的推测,意为“一定已经”。
※ Mr. Li must be working now, for the lights in his office are
still on.
李先生一定在工作,因为他办公室的灯仍然亮着。
must 的用法
新课探究
must 表推测只能用于肯定句。mustn’t 表示“禁止;不准”。如果要表示“一定不;肯定不”的意思,应用 can’t。
※ You mustn’t play outside when it is raining.
下雨时,不准在外面玩。
can 表示推测“可能性”时,往往用于否定句或疑问句。
※ He can’t be at home.
=It is impossible that he is at home.
他不可能在家。
could 可用于表示某事有可能发生或可能是事实,语气不
是很肯定。
※ Don’t eat it. It could be poisonous.
不要吃它,它可能有毒。
can 和 could 的用法
couldn’t 用于否定推测,表示某事不可能是事实,但自己也不能肯定。
※ It couldn’t possibly be Tom, for he should be at school now.
这不可能是汤姆,因为此时他应该在学校。
may/might 表示推测“可能性”时,意为“可能,也许”,语气没有 must 肯定。
※ He may/might be an American.
=It is possible that he is an American.
他可能是个美国人。
may 和 might 的用法
may/might 表推测时,可以用于否定句,意为“可能
不,也许不”,但不用于疑问句。
※ He may/might not be at home, but I am not sure.
他也许不在家,但我不确定。
表示推测时,may not 意为“可能不”,can’t 意为
“不可能”,前者较后者语气弱得多。
Choose the best way to complete each sentence using the words in brackets.
4a
1. A: Where’s Jean
B: I’m not sure. She __________ (is/might be/must be) in the laboratory.
might be
2. A: Everyone is going to the pool after school.
B: Really It ________ (must be / can’t be /could be ) hot outdoors.
must be
3. A: That’s the phone.
B: Hmm. I wonder who it __________ (must be / could be / should be).
could be
4. A: I wonder if there are Jim’s glasses.
B: They _________ (can’t be / might be / could be) his. He doesn’t wear glasses.
can’t be
5. A: I hear water running in the bathroom.
B: It _________________ (could be / must be / can’t be) Carla. She was thinking of taking a shower.
could be / must be
Complete these responses.
4b
1. A: Many people are wearing coats.
B: The weather must be ______________________________.
2. A: Sally has been coughing a lot.
B: She might be _______________________.
getting colder / cold outside
having a sore throat / ill
3. A: This restaurant is always crowded.
B: The food _______________________.
4. A: Whenever I try to read this book, I feel sleepy.
B: It can’t __________________.
be very interesting
must be delicious
Look at this picture of a room. How much can you tell about the person who lives here Is it a boy or a girl What are his/her hobbies Discuss your ideas with a partner.
4c
It could be a girl’s room because it’s very tidy.
I guess so. But it might be a boy’s room because the clothes look like boys’ clothes.
Ⅰ.根据句意及首字母或汉语提示填写单词
1. I didn’t sleep well last night. So I now feel very s_________.
2. There’s something _________(贵重的)in the safe.
3. —W_________ handbag is this?
—It’s my mother’s. She bought it yesterday.
4. The weather made it impossible to be _________(在室外).
leepy
hose
valuable
Practice
outdoors
1. —On my way to the bookstore, I saw Mary hanging out with
her friends.
—It _____ be her. She has gone to Beijing.
A. can’t B. mustn’t C. might D. could
2. The little boy has just had lunch. He _____ be hungry already.
A. must B. mustn’t C. can D. can’t
Ⅱ.单项选择
√
√
3. —Whose book is this?
—It _____ our geography teacher’s. You see, his name is on it.
A. can’t be B. can be C. mustn’t be D. must be
4. —He _____ be in the classroom, I think.
—No, he _____ be in the classroom. I saw him go home a minute ago.
A. can; may not B. must; may not
C. may; mustn’t D. may; can’t
0
√
√
1. Are ________(wolf) dangerous to people
2. He looked ________(easy) and refused to answer questions.
3. —How did you find the way to the hotel in the end
—By asking two __________(policeman) for help.
4. There must be some boys________ (play) soccer near our house.
policemen
Ⅲ.用括号中所给单词的适当形式填空
playing
uneasy
wolves
1. Retell the passage in 3a.
2. Review the words and expressions of Section A.
Homework
THANK YOU