允许
We can board now.
Obligation: You must fasten your seat belts. 义务 (strong) You should pay attention. (weak) You ought to pay attention.
Possibility: 1 It may rain. 可能性 2 How could I forget an important thing like that? 3 He can’t /couldn’t have known the result.
根据汉语完成句子。
1. A: _M__a_y_I_g_o__w_i_t_h_f_r_ie_n_d_s__(我可以跟朋友 去) to the harvest festival? B: Yes, you may.
2. A: If I want to be a doctor, _s_h_o_u_l_d_I_s_t_u_d_y _sc_i_e_n_c_e_ (我应该学理科吗)? B: I think so.
eg. Could you lend me your dictionary? Could I use your bike?
3. can/could have done可能做过/本可以 can’t /could’t have done 不可能做过 eg. They can't have gone out because the light is still on.
Unit 1
Modal Verb I
There are things that must be done That are not yet begun Things that I must do When I want to be with you Although we’re far apart You’re with me in my heart No one else will do I just want to be with you
在肯定句中，may 的可能性比can 高， may 表示现实的可能性，can 表示理论 上的可能性。
在疑问句中，表示可能性用can。 如：Where can he be? 他会在哪呢？
C. 表示祝愿; 但语气较正式: eg. May you succeed! May you have a good journey!
（一般用于否定句和疑问句中）
eg. Can the news be true? C. 在口语中, can可以表示请求或允许：
eg. Can I sit here?
2. could的主要用法是： A. could 是can的过去式, 表示与过去 有关 的能力和推测: eg. We all knew that the young man couldn’t be a doctor. B. could可以代替can表示请求, 但语气较 can委婉:
I want to be with you Can’t you hear me? I need you near me I want to be with you I need you near me, my love
The two of us are one Mother of my son No one else will do I just want to be with you
5. You should have told him a week ago. 你本来应该在一周前告诉他的。
6. Can you give me some suggestions? 你能给我一些建议吗？
7. They wanted to know when you would go to the park. 他们想知道你们什么时候去公园。
我可以和你说句话吗？
will和would
will/would 表请求 (would 语气比will委婉)
Will you tell her that I'm here? 请您告诉她说我在这儿，好吗？
Would you help us, please? 请您帮助我们，好吗？
I’d go there with you. （表意愿） 我要和你一块到那儿去。 Your teacher wouldn’t allow it.（表许可） 老师不会允许这件事。
---She _m_a_y__(m__i_g_h_t)__h_a_v_e_g_o_n_e_ (可能上班) by bus.
9. Mike _c_a_n_’_t_h_a_v_e_f_o_u_n_d_ (一定还没有找回) his car, for he came to work by bus this morning.
Read the text again and pay attention to modal verbs like may, might, will, would, can, could, shall, should and must.
什么是情态动词？ (Modal Verbs)
情态动词表示说话人的某种 感情或语气，对某一动作 或状态的某种态度。 表示“需要、可以、 必须、应当”等。
Ability: 1 He can speak English now.
能力 2 He couldn’t speak English a
year ago.
3 I’m not able to come to the game
on Friday.
Permission: All passengers may now board.
shall和should
1. shall用于构成将来时是助动词。 2. shall用于征求对方的意见（一，三人称）
e.g:Shall we put off the sports meeting until next month?
Shall Tom go there with me tomorrow?
may和might
may 常用来表示： A. 表示请求、允许：
比can较为正式:
eg. May I come in ?
You may go now. B. 表示说话人的猜测: “也许” “可 能”: 通常只用于肯定句和否定句中。
eg. --I believe the man is from England. --But I may be wrong. The guest may arrive this afternoon.
3. 情态动词的“时态”形式并不是时间 区别的主要标志，不少情况下，情态动 词的现在式形式和过去式形式都可用来 表示现在时间、过去时间和将来时间。
can和could
1. can的主要用法是： A. 表示体力或脑力的能力：
eg. The girl can dance very well. B. 表示说话者的推测﹑事物的可能性:
I want to be with you Can you hear me? I need you near me I want to be with you I need you near me, my love
The BONZO DOG BAND are a band created by a group of British art-school denizens of the 1960s. They combined elements of music hall, trad jazz, psychedelic rock, and avant-garde art.
7. Philip _m_a_y__(m__i_g_h_t)__h_a_v_e_b_e_e_n__h_u_r_t____ _s_e_ri_o_u_s_ly__in__t_h_e_c_a_r__a_cc_i_d_e_n_t__(可能在车 祸中受了重伤).
8. ---Linda has gone to work, but her bicycle is still here.
might 的用法有: 1.多在间接引语中表示过去的可能和 允许。如:
She said that he might take her bike. 她说他可以拿她的自行车去用。
2.表示现在的可能，其可能性要比 may 小。如： He might go home tomorrow.
说不定他明天会回家。 3.表示现在的许可，语气比may 较委婉， （一般用于疑问句 ） 如: Might I have a word with you?
5. The road is wet. It _m__u_st__h_a_v_e_r_a_i_n_e_d_ (肯定下雨了) last night.
6. Your mother __m_u_s_t_h_a_v_e__b_e_e_n_l_o_o_k_in__g_ f_o_r_y_o_u_ (一定一直在找你).
3.shall 用于二，三人称的陈述句中，表示 说话人给对方的命令、警告、允诺或威胁。 e.g:You shall fail if you don’t work hard.
（警告）
He shall have the new book when I finish reading that one.
（允诺）
情态动词的语法特征
1.情态动词 不能单独做谓语 (除ought 和have外)
2. 情态动词没有人称，数的变化，但有 些情态动词，如can, will也有一般式 和过去式的变化。
只作情态动词的
can/could, may/might, ought to, must 可情态可实义的 need, dare/dared 可情态可助动词的 shall/should, will/would 相当于情态动词的 have to, used to