学历提升分享：自考英语语法不定式的三种形式

动词不定式的进行式、进行式和进行进行式：这三类在考试题中产生的频次很高，要需注意动词不定式的这三种方式。

1、假如动词不定式所表达的姿势与关键宾语所表达的姿势(情况)与此同时(或基本上与此同时)产生或出现在关键宾语以后，那麼用动词不定式的一般方式

He received a warm welcome from the Australians and from his family who had flown there to meet him.

In 1967, he arrived back in England, where a quarter of a million people were waiting to welcome him.

After all, eighty was a special birthday, another decade lived or endured just as you chose to look at it.

Now suddenly she began to sob, holding herself in as if weeping were a disgrace.

2、假如动词不定式所表达的姿势(情况)产生在关键谓语动词或指定的某時间以前,那麼动词不定式就需要用其进行式

She feels relaxed to have finished writing her thesis before the deadline.

1)The Vikings are believed America.

[A] to have discovered[B] in discovering[C] to discover[D] to have been discovered

2)The students were to at the auditorium before 1:30 pm, but the lecture was cancelled at the last minute.

[A] assembled [B] have assembled [C] assembling [D] be assembled

3)He was to the new ambassador, but he fell ill.

[A] having telephoned[B] have telephoned[C] has telephoned[D] telephoning

3、动词不定式进行式表明关键谓语动词所表达的姿势(状况)产生时,动词不定式所表达的姿势已经产生

When he came in, I happened to be doing my experiment in the lab.

Why do you stand here?You are supposed to be working in the workshop.

4、动词不定式进行进行式表明其形容词所表示的姿势，在关键谓语动词所表示的操作以前一直在开展

The students from the Department of Sociology are said to have been investigating the possibility of producing the new product.

They are quite happy to have been cooperating harmoniously with us till now.