Section_ⅣGrammar & Writing

　　语法图解

　　探究发现

　　①I am speaking in favour of the Internet.

　　②There are two main points which must be included when we analyse the Internet.

　　③With the touch of a button or the click of a mouse, a student will find abundant information.

　　④These problems do not occur as often when people use traditional reference materials.

　　⑤To help solve this problem, a special clinic was opened in Beijing in 2005.

　　⑥One university did a study about the students who had dropped out.

　　[我的发现]

　　(1)按英语词类划分，以上各句中黑体部分的词均为助动词。

　　(2)以上各句中黑体部分的词均无词汇意义，不能单独作谓语。

　　(3)②⑤句中黑体部分的词在句中与实义动词一起构成被动语态。

　　(4)①③⑥句中黑体部分的词在句中与实义动词一起构成某种时态。

　　(5)④句中黑体部分的词在句中与实义动词"occur"一起构成否定形式。

　　一、助动词的概念

协助主要动词构成谓语动词词组的词叫助动词。被协助的动词称作主要动词(Main Verb)。助动词是语法功能词，自身没有词义，不可单独使用，它没有对应的汉语翻译，用于构成时态、语态。