as if,as though的用法：

這兩個複合從屬連詞的用法和意義完全一樣,但as if 在當代英語中比 as though 普通得多.

as if 引出的方式狀語從句所表示的情況是事實或具有很大可能性時,通常用直陳語氣.名子的謂語我為look,seem,taste,smell,sound等.如：

It looks as if they have succeeded in the experiment.看來好像他們試驗成功了.

as if 引出的方式狀語從句所表示的情況不是事實,而是主觀想象或誇大性的比喻時,通常用虛擬語氣.從句中謂語動詞一般用過去時,be 動詞常用 were,但在現代英語中也常見到單數 was的情況.如：

The young man with long hair looks as if he were a girl.這位滿頭長髮的男青年看上去像個女的.

The injured man acted as if nothing had happened to him.這位受傷的男子表現得好像沒發生什麼事一樣.

as if 引出的方式狀語從句,當主句謂語是過去時態時,從句謂語形式常常沒有什麼特殊之處.如：

The lady felt as if she lost something.這位女士好像學得丟了什麼東西.

He was singing as though / if he hadn"t had / didn"t have a care in the world.他唱著歌,好像人世間他沒有憂慮.

as if 引導的同一從句中所用的時態不同,意思往往不同.請比較：

The clown looks as if he were ill.那個小丑好像害病似的.（虛擬語氣）

The clown looked as if he had been ill.那個小丑過去好像生過病.（過去生過病或虛擬語氣）