68语气助动词小结

    英语语法进深──博客

68语气助动词小结( a brief summary of modals) (三)                                     3/24/2014

“语气助动词” 如,  can, could, will, would, should, may, might, must, ought 和 shall 等 .它们帮助本动词说明句子的语气意念.  有关语气助动词的极其重要的一方面是如何形成句子的过去时制.  因为would, should, could 和 might等在这里不是表示过去时间, 而是表达一般时间, 所以要用这些助动词(包括may, must 和 ought) 来表示过去一定形式的时候, 必须另外把本动词变成 “完了时制”(perfect tense).  句子如:  He could do it ( could表一般时间), 但句子写如,  He could have done it (则could have done表示在过去时间发生的). 这种习惯的使用表达方式,  委实难为了我国学生, 除了化时间去记忆它们的习惯用法外, 似乎没有快捷的方式可寻.  它们的千变万化, 委实需要用悟性及耐力去捉摸.  一旦融会贯通, 那么你写的, 说的英语就是依英美人士的思想方法.  下面的例句都极其重要, 要多多仿效.

     例如,  If the other banks had not helped, that bank would have failed.

                Who could have done this?
                You may have heard the story before.
                You should have heard him talk at the dinner.
                 I should have run away.
                 You should have resigned.
                 He could not have seen me, because he was not there.
                 There’s no body at home.  They must have gone out.
                  She might have left her bag in the store.

练习三十九 :

 

     should have, could have, may have, might have, must have这些短语都极其重要.  试用它们造
   句.

语气助动词小结 :

1.  请求别人做一些事(requests) : 常用 can 或 could.

     例如,   Can you wait a moment, please? 或 Could you wait a moment, please?

                 Paul, can you do me a favor?
                 Excuse me, could you tell me how to get to the airport?
                 I wonder if you could help me.
                 “Do you think you could ...?” (不常用 “can”):

       间或我们也用  will 和 would 请求别人做一些事 (但是 can 和 could 用得比较多):

           例如,   Paul, will you do me a favor?

                       Would you please be quiet?  I'm trying to concentrate.

  2. 询问别人一些事(asking) : 常用Can I have ...?  或 Could I have ...? 等语气助动词的形式.

          
            例如,    Can I have these postcards, please? (在礼品店)
                             Could I have the salt, please?  (在进餐时)

                 [注] : 此时也可用 May I have ...? (不寻常):

 

                 例如,   May I have these postcards, please?  (有些過分形式 ‘formal’)
                             May I have the salt, please?

          3. 请求和给予别人允诺做某些事 (permission ) :  请求允诺通常用 can, could 或

               may.

    例如,   Hello, can I speak to Peter, please?

                            “Could I use your phone?”  “Yes, of course.”
                            Do you think I could borrow your bike?
                            “May I come in?”  “Yes, please do.”

               给予允诺通常用 can 或 may.
 

              [注] : 一般用 can 或 could 比较习惯性, 因用 may 常常过于形式, 用得少些.

          4.   提供给别人服务(Offering) : 常常用 Can I ...? 或 may I….?  但是提供做事时,

                用 May 不太寻常, 因太正式.

             例如,   “Can I get you a cup of coffee?”  “Yes, that would be very nice.”

                          “Can I help you?” “No, thanks. I’m been helped.”
       
          5.      提供和邀请(Offering 和 inviting) : Would you like ...? 这句问话是常常挂在美国人口边
        的话, 多多练习在社交场合中使用, 很讨人喜欢.

       例如,   “Would you like a cup of coffee?”  “Yes, please.”

                            “Would you like to go to movies with us Saturday night?” “Yes, I’d love to.

比较  must (not) have done与  couldn't : 因为  must (not) have done 比较繁琐而不如用couldn't 来
    得寻常及简便.

例如,   He walked past me without speaking.  He couldn't see me.

                He walked past me without speaking.  He must not have seen me.
                Stephen walked straight into the wall.  He couldn't look where he was going.                                      Stephen walked straight into the wall.  He must not have been looking where he
                     was going.

比较  might not  与   couldn’t :   couldn't (否定式) 与 may not 和 might not 的表示的意思有些差
    别.   前者有不可能的意思, 而后者有或许的意味.

       例如,    She was too far away, so she couldn't have seen you. (因为太远了, 她不可能
                   看到我)
                    Stephen : I wonder why she didn't say hello.
                    Paul :      She might not have seen you. (或许她没有看到你, 或许她看到你)

    但 may, might 与could 在肯定句中, 可以通用.