名詞性從句只有表語從句,但還可以引導(dǎo)狀語從句.
as if 是連詞詞組,相當(dāng)于 as though ,意為“好像,好似”,引導(dǎo)表語從句和狀語從句.
1 .as if 引導(dǎo)表語從句.
as if 引導(dǎo)表語從句時(shí),可以和 as though 互換,其句型為：“It looks / seem as if …”,其中 it 本身無詞義,是無人稱代詞,looks / seems 是連系動詞,as if 引導(dǎo)表語從句.例如：
It looks / seems as if you have got no experience .看來你似乎并沒有經(jīng)驗(yàn).
2 .as if 引導(dǎo)方式狀語從句.
as if 引導(dǎo)的方式狀語從句中,從句中的動詞一般要用虛擬語氣.若表示與現(xiàn)在事實(shí)相反的主觀設(shè)想,動詞用過去式 (be 用 were ,適用于各種人稱)；若表示與過去事實(shí)相反的主觀設(shè)想,動詞用“had + 過去分詞”形式.例如：
He acted as if he were smoking .他那舉動好像他抽煙似的.
They talked as if they had been friends for years .他們說話很親熱,就像多年的老朋友似的.