北京 杨 岚

unless、as soon as和so...that...都是连词，它们各自都可以用来引导不同的状语从句。

◎用法梳理

◆unless从句

unless意为“除非；如果不”，引导条件状语从句。unless引导的条件状语从句表示否定意义，相当于if引导的条件状语从句的否定形式，即“if...not...”。 例如：

We will go on a picnic this weekend unless it rains.=If it doesn't rain，we will go on a picnic this weekend.如果这个周末不下雨，我们将会去野餐。

Unless he allows me to leave，I can't leave here.如果他不允许我离开，我不能离开这里。

◆as soon as从句

as soon as意为“一……就……”，用来引导时间状语从句，表示主句动作紧接着从句动作发生。例如：

Mary turned on the TV as soon as she got home.玛丽一到家就打开了电视。

They will start as soon as Robert arrives.罗伯特一到他们就动身。

【知识拓展】

1.通常情况下，在含有unless或as soon as的复合句中，如果主句用一般将来时或主句的谓语部分含有情态动词，它们引导的从句常用一般现在时。

2.在复合句中，unless或as soon as引导的状语从句可以放在主句之前，也可放在主句之后。当从句位于主句之前时，常用逗号将其与主句隔开。

◆so...that...从句

so...that...意为“如此……以至于……”，用来引导结果状语从句。常见结构为“so+形容词/副词+that从句”和“so+形容词+a/an+单数可数名词+that从句”。例如：

He was so excited that he couldn't say a word.他如此兴奋以至于一句话也说不出来了。

Helensangsowell that everybody cheered her.海伦唱得如此好，以至于每个人都为她喝彩。

It is so interesting a book that I want to read it again.这本书如此有趣，以至于我还想再读一遍。

【知识拓展】

1.so...that...有时可与too...to...和...enough to...结构进行转换，通常分为下面两种情况：

（1）如果that引导的从句是否定句，且主句和从句的主语相同，那么so...that...可转换为too...to...结构；如果从句和主句的主语不同，so...that...则可转换为too...for sb.to...结构。例如：

He is so young that he can't do it.→

He is too young to do it.

Tom spoke so fast that we could hardly follow him.→

Tom spoke too fast for us to follow.

（2）如果that引导的从句是肯定句，且主句和从句的主语相同，那么so...that...可转换为...enough to...结构；如果从句和主句的主语不同，so...that...则可转换为...enough for sb.to...结构。例如：

Her brother is so strong that he can move the heavy box.→

Her brother is strong enough to move the heavy box.

The problem is so easy that all the students can work it out.→

The problem is easy enough for all the students to work it out.

2.such...that...也意为“如此……以至于……”，用来引导结果状语从句。常用结构有 “such+a/an+形容词+单数可数名词+that从句”和“such+形容词+复数可数名词/不可数名词+that从句”。例如：

It is such an interesting movie that I have seen it three times.这部电影如此有趣，以至于我看了三遍。

It was such fine weather yesterday that we went boating.昨天天气很好，我们便去划船了。

【温馨提示】当名词前的形容词是many、much、few、little时，such要改为so， 即 “so+many/much/few/little+名词+that从句”。例如：

There was so much work to do that everybody got bored.有这么多的工作要做，人人都感到厌烦了。

3.so that意为“以便……；为了……”，用来引导目的状语从句，从句中常含有can、may等情态动词。so that还可以表示“因此；所以”，用来引导结果状语从句，在so that前可以使用逗号。例如：

Jim studies hard so that he can go to a good senior school.吉姆努力学习以便能考上好的高中。

Yesterday morning he got up early，so that he caught the first bus.昨天早晨他起得很早，因此他赶上了早班车。

◎中考链接

1.In summer，food will go bad quickly_______we put it into a fridge.

【2018·兰州中考题】

A.ifB.unless

C.as soon asD.while

【答案与解析】B句意：在夏天，我们要把食物放进冰箱，否则食物很快就会坏。根据常识可知，在夏天要想食物不变坏，就要把它放进冰箱里。unless相当于if...not...，用来引导条件状语从句。故选B项。

2.Shestoppedtalking_________her mother came into the room.

【2018·宜宾中考题】

A.as soon as

B.unless

C.though

【答案与解析】A句意：她的母亲一进房间，她就停止了谈话。根据句意可知此处要用表示“一……就……”的as soon as引导时间状语从句。故选A项。

3.—What a mess！The sharing bikes are thrown everywhere.

—Let's collect and put them in the right place_______they can be used conveni-ently.

【2018·东营中考题】

A.unlessB.so that

C.becauseD.so long as

【答案与解析】B句意：——真是一团糟！共享单车被丢得到处都是。——让我们把它们收集起来放在合适的地方，这样就可以被方便地使用了。根据句意可知，此处应用表示“以便；为了”的so that来引导目的状语从句。故选B项。

4.—Harry Potteris_______an interesting novel_______I want to read it again.

—I agree with you.

【2018·咸宁中考题】

A.so；thatB.too；to

C.such；thatD.as；as

【答案与解析】C句意：——《哈利·波特》是一本如此有趣的小说，我还想再读一遍。——我同意你的看法。第二个空白处后面是一个句子，排除B、D项。novel是名词，排除A项。故选C项。

5.Hefelt_______surprisedthat he couldn't say a word with his mouth wide open.

【2016·内江中考题】

A.veryB.such

C.soD.too

【答案与解析】Cvery和too后面不能接句子，排除A、D项。surprised是形容词，应用so修饰。故选C项。

◎自我检测

Ⅰ.选择正确的答案填空。

1.Tina is_______nervous_______she can't talk in front of the class.

A.such；that

B.too；to

C.so；that

D.enough；to

2.Your dream will not come true_______you keep trying your best.

A.whenB.unless

C.whetherD.because

3.—Did you catch the early bus this morning?

—Yes.Thebusstartedtomove_______I got on it.

A.thoughB.before

C.as soon asD.ever since

4.I looked through the test paper again and again_______I wouldn't make any mistakes.

A.ifB.because

C.even thoughD.so that

Ⅱ.按要求完成下列句子。每空一词。

1.I can't give you any money unless you tell me what you want to buy.（改为同义句）

I can't give you any money_______you_______tell me what you want to buy.

2.He is so young that he can't look after himself.（改为简单句）

He is_______young______________after himself.

3.The boy saved money in order to buy his mother a present.（改为复合句）

Theboysavedmoney_______ _______he could buy his mother a present.