二、助动词的分类

类别 例词 特点 基本助动词 be, do, have 无词汇意义，只有语法作用，协助主要动词构成时态、语态、否定句、疑问句等 助动词短语(半助动词) be about to, be due to, be going to, be likely to, be meant to, be supposed to, be willing to, have to, seem to, be unable to, be unwilling to 在功能上介于主要动词和助动词之间的一类结构 其他助动词 will, shall, should，

would 无词义，主要用来构成将来时 　　

　　[即时演练1]　用适当的助动词填空

　　　①In the past, many students did not know the importance of English.

　　②I haven't seen him for a long time.

　　③Only when we began our college life did we realize the importance of English.

　　④He will come to the office this afternoon.

　　⑤These books are not supposed to be taken out of the reading­room.

　　三、基本助动词的用法

　　1．助动词be的用法

用法 例句 be ＋现在分词，构成进行时态 English is becoming more and more important.

They were having a meeting. be ＋过去分词，构成被动语态 English is taught throughout the world.

The window was broken by Tom. be ＋动

词不定式 表示最近、未来的计划或安排 He is to go to New York next week. 表示命令 You are to explain this. 　　

　　[即时演练2]

　　(1)用所给动词的适当形式填空

　　①(重庆高考改编)James has just arrived, but I didn't know he was_coming (come) until yesterday.

②(北京高考改编)-Hi, let's go skating.