need 和dare 的两种形式的用法
五、情态动词的知识难点解析
知识难点：
某些情态动词的特殊用法：
need 和dare 的两种形式的用法
need 和dare可以用做实义动词，后面接不定式(to do)结构，在疑问句和否定句中，加助动词do/does/did/或don’t/doesn’t/didn’t。作为情态动词使用时，主要用于疑问句和否定句中。情态动词needn’t(没有必要，不必)相当于don’t have to
例句：
1. It is cold, you need to wear some warm clothes.
2. Need I stay here with you for a while ? Thank you, you needn’t.
3. How dare you speak to parents like that ?
注意：
句型I dare say+从句。 意思是：我肯定…… = I’m sure或There is no doubt that+从句。
例句：
I dare say that my uncle will get the money if I die.
will和would
表示“意志”或“愿意”，would 则指过去愿意做……
例句：
1. He said that he would help us.
2. You may telephone if you will accept this job.
would可以表达“过去习惯做……”类似于“used to do”
例句：
1. When we were children, we would go swimming every summer in that river.
表示请求，固定的句型：Will/Would you please do…? / Would you like to do…?
例句：Will/Would you please give him a message when you see him ?
shall
1. 用于第*，三人称，表示“请求”;“建议” 或“推荐”
例句：
1. Shall we start the meeting now?
2. Shall I watch TV now ?
3. Shall my son carry the case for you ?
2. 用于第二人称，表示“命令，“要求”，“许诺”
例句：
1. You shall take whatever you like.
2. You shall not go to the party with me if you make so much noise again.
在表示推测的否定句或疑问句中，常用can /can’t /could / couldn’t表示，意思是：“可能…吗?”;“…不可能…”。而不能使用mustn’t或must等词。
