when, while, as, before, after, since, until, as soon as, once, the moment
主从句时态一致:若主句是将来时,从句用一般现在时(“主将从现”)
when某一时间点或时间段
When the bell rings, students stand up.
while 强调动作同时进行,从句动词需延续性(如be doing)
While I was sleeping, my phone rang.
as(伴随性动作或“一边…一边…”)
As spring comes, flowers bloom.
条件状语从句
if, unless(= if not), as long as(只要), provided that(假如)等
主将从现
if
If it rains tomorrow, we will stay at home. (if从句用现在时,主句用将来时)
unless=if not:
You'll fail unless you work hard.
虚拟条件句需用特殊时态(如If I were you...),unless不可与否定词连用(如unless you don’t go)
原因状语从句
because/since/as/now that(既然)
because:直接原因,语气最强,回答“why”问题。
He failed because he didn’t study.
since/as:已知原因,语气较弱,常位于句首。
Since you are busy, I’ll do it myself.(既然你忙,我自己来。)
now that:强调“既然(某一新情况)
地点状语从句
where/wherever
Put the book where it was.(把书放回原处。)
Wherever you go, I’ll follow you.
目的状语从句
so that/in order that
从句中常含情态动词(can, may, could等)
She studies hard so that she can pass the exam.
简化表达:She studies hard to pass the exam.(不定式表目的)
结果状语从句
so...that(如此…以至于), such...that
so + 形容词/副词 + that
It was so cold that the lake froze.
such + (a/an) + 名词 + that
He is such a kind man that everyone likes him.
让步状语从句
although, though, even though, even if, no matter how/what/who等
不可与but连用(Although it’s hard, but I’ll try. → 去掉but)
Although he is rich, he lives simply.
even if:假设性让步(即使)
no matter:后接疑问词(how, what等)
No matter what you say, I won’t believe you.
方式状语从句
as, as if/as though(仿佛)
as按照,如同——真实情况
(陈述语气)
He did it as I taught him.
as if/as though好像,仿佛——非真实或不确定
(虚拟/陈述语气)
省略从句:
as if 后可省略主语和动词,直接跟形容词、介词短语等:
He waved his hands as if (he was) crazy.(他疯狂地挥手。)
She left as though (she was) in a hurry.(她离开时好像很匆忙。)
与 like 的区别:
like 是介词,后接名词或代词,不能接完整从句(非正式口语中可用 like 代替 as if,但写作中不推荐):
He acts like he owns the place.(口语)
He acts as if he owned the place.(正式)
虚拟语气与陈述语气的选择:
当说话者认为情况可能为真时,用陈述语气;
当明显与事实相反时,用虚拟语气。