英语语法：助动词

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

　　一、have/has (现在完成时), had (过去完成时)

　　这组助动词主要用来构成完成时态，形式为：have /has /had + 过去分词如：

　　She had mentioned this before.

　　I haven't seen you for ages.

　　二、be

　　be本身可作谓语动词，但在进行时中它是助动词，与现在分词搭配使用，缺一不可如：

　　He's looking for his favorite pet.

　　She's watching a football match.

　　此外，be和过去分词搭配构成被动语态

　　如：The vicar was killed in a car accident.

　　三、do/does (一般现在时), did (一般过去时)

　　此组助动词用于构成疑问式或否定式如：

　　Did you meet the manager this morning?

　　He doesn't feel like smoking at the moment.

　　四、will, shall, would

　　此组助动词用于构成将来时如：

　　Mary promised she would pay you a visit soon.

　　He won't be able to see you until an hour later.

　　例题：

　　(1)

　　The colors of a rainbow ---- arranged in the same order.

　　(A) which are always

　　(B) and they are always

　　(C) always

　　(D) are always

　　答案：D

　　解释：空格前是句子的主语，之后是过去分词短语，空格处需要补全句子的谓语，A使原句只有从句无主句;B并列句的前一个分句无谓语;arrange与color是被动关系，C是主动式，可排除;只有D助动词are恰好与arranged构成句子的谓语