深圳市宝安中学 赵国强
句首可以对某些句子结构产生制约和影响，这是在学习中不应忽视的重要内容。着眼于句首可以把握和处理好语言结构，使整个句子表达规范，结构精当。句首的以下两个特点需要引起重视。
一句首制约着句子，使有些结构的选择范围较句中相对狭隘
1.句首的“是否”不用if，而只用whether。例如：
Whether we’ll go out depends on weather.我们是否出去要看天气。
2.如果主语从句没有连接代词或连接副词（如whether/what/how等）引导，就必须在从句之前加上that，该连接词不可省略。例如：
That we need more equipment is quite obvious.我们需要更多设备，这是显而一见的。
3.句首动名词的逻辑主语大多不用名词普通格或代词宾格，而用名词所有格或物主代词。例如：
The soldier’s being killed in the war is her one regret.那位战士的阵亡是她的一件憾事。
His recognizing the faults is a good thing.他认错，这是好事。
4.句首的目的状语，不用so as (not) to do，而只用in order (not) to do或(not) to do等。試比较：
In order to(或To) catch the first bus, Li Hua got up very early.= Li Hua got up very early in order to/ so as to(或to) catch the first bus,.为了赶上头班车，李华起的很早。
5.句首的(not) until多不用till替换。例如：
Until then I had known nothing about it.(= Not until then had I known nothing about it.)直到那时我才听说此事。
6.表示“正如”意义的关系代词在句首只用as。如：
As is known to us, Taiwan belongs to China.(= Taiwan belongs to China, as/ which is known to us)我们都知道，台湾属于中国。
二句首某一词语或结构的出现，直接影响句子，使结构随之变化
1.句中的否定词提于句首，其主谓语必须倒装。如：
Never before have I seen him.以前我从未见过他。
Hardly had he fallen asleep when he dreamt a sweet dream.他刚睡着便做了个美梦。
Not a single mistake did the top student make in the test.那位尖子生在考试中一个错误也没犯。
The boss didn’t let out the secret. Neither/Nor did his secretary.老板没有泄密，他的秘书也没有（这样）。
2.方位副词、方位介词短语或某些时间副词于句首，如果主语是名词，谓语是不及物动词或系表结构，谓语动词直接放到主语之前进行完全倒装。注意：这种倒装句不用进行时态。现分别举例如下：
Here are some registered letters for you.这儿有你的几封挂号信。
Between the two buildings stands a monument to the hero.在两栋楼房之间矗立着一座英雄纪念碑。
Now comes your turn.现在轮到你了。
比较： Out rushed the boys.孩子们冲出去了。（主语是名词，须倒装。）
Out they rushed.他们冲了出去。（主语是代词，无需倒装。）
On the grass dances a little girl.（＝A little girl is dancing on the grass.）有个小女孩在草地上跳舞。
3．原因、时间、条件等否定状语从句改为简单句，否定词not应从谓语中的某一位置提于句首。如:
He wrote another letter as he had not received an answer.= Not having received an answer, he wrote another letter.由于没收到回信，他又写了一封。
4．Only引导状语或状语从句，其后的句子或主句的主谓语必须倒装。如：
Only in this way is it possible to master a foreign language.只有用这种方法才可能掌握好一门外国语。
Only when the war was over was he able to get happily back to work.只是战争结束之后，他才得以愉快地返回工作岗位。
注意：句首only所引导的短语作主语或宾语则不可倒装。試比较：
Only last Saturday he spent at home.就上周六他是在家里度过的。
Only last Saturday did he stay at home.就上周六他在家里度过。
5．表示部分意义的so置于句首，该句子倒装。如：
So frightened is he that he can’t move at all.他吓得不敢动弹。
She sings badly, so does everyone in her family.她唱不好歌，她全家人都是这样。
比较：You are tired. So am I.你累了，我也是。
You are tired. So am I.你累了，我也是。
“You are tired.”“ So am I.”“你累了。”“我的确累。”
本文曾发表于《中学英语指导》1999年第8期