as if和as though引導(dǎo)的從句所敘述的情況與事實(shí)相反時(shí)，從句的謂語動(dòng)詞多用虛擬語氣。在虛擬語氣結(jié)構(gòu)中，用________時(shí)態(tài)來表示現(xiàn)在的情形；用________時(shí)來表示過去的動(dòng)作或狀態(tài)；用________時(shí)表示正在進(jìn)行的動(dòng)作；用________時(shí)表示將要發(fā)生的動(dòng)作。

當(dāng)as if和as though從句的主語和主句主語一致，且從句中含有系動(dòng)詞be的某種形式時(shí)該主語和系動(dòng)詞可以省略。

例如：John paused as if(he was)expecting Mary to speak．

Choose the right description of the part of sentence underlined．

(選出對(duì)句子畫線部分結(jié)構(gòu)描述正確的選項(xiàng)。)

It seemed that the world was at an end!

A．主語

B．表語

C．賓語

同位語從句與定語從句的區(qū)分

1)The proposal that he put forward is to be discussed at the meeting．

2)The proposal that we should hold sports meeting is to be discussed．

a．句1)是________從句，that在從句中________成分，句2)是________從句，that在從句中________成分，而且一般不省掉。

b．定語從句用來說明先行詞的性質(zhì)特征，起修飾或限制作用；同位語從句用來解釋說明句詞的內(nèi)容，二者是________關(guān)系。

c．區(qū)分時(shí)可以在先行詞與從句之間加一個(gè)系動(dòng)詞be，使之構(gòu)成一個(gè)新句子，如果句子通順且符合邏輯，則為同位語從句，反之，則為定語從句。

例如：The report that he was going to resign was false．他將辭職的傳聞是假的。因?yàn)閠he report was that he was going to resign句意通順，所以，that he was going to resign是同位語從句。