(
课件网) 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 ... ...
