镣铐时间状语从句和让步状语从句

2021年1月14日发(作者：曹格)
时间状语从句和让步状语从句
一、时间状语从句
1．(1)when引导的从句的谓语动词可以是延续性的动词，又可以是短暂性动词。
when有时表示“就在那时”，常构成be about to...when...结构，
We were about to leave when she called.
When we lived in town we often went to the theatre.

(2)as引导的动作是延续性的动作，可以表示主句和从句动作同时发 生，意为“一
边……，一边……”；as也可以强调“一先一后”。
As we were going out，it began to rain.
She always sings as she dances.

(3 as soon as表示“一……就……”，类似的结构还有：the minute，the moment，
the time，the instant，immediately，hardly...when，no sooner...than等。

Hardly/No sooner had they left when/than it began to rain.
Tell him the truth as soon as he arrives.

2．通常since引导从句的动词是终止性动词，其主句用现在完成时或现在完成
时。
It has been three months since she wrote to me.＝It is three months since she
wrote to me.

二、让步状语从句
1．让步状语从句常由下列连词引导：
though，although，as，while，even if，even though。
Though it’s hard work，I enjoy it.
While I did well in class，I was a poor performer at games.

2．whatever，whenever，wherever，whoever，whic hever，however在引导让
步状语从句时，相当于no matter what (when，where，who，which，how)，表
示无论在什么条件下进行随意的选择。
Whatever(No matter what)you may think，I’m going ahead with my plans.

3．在however引导的 让步状语从句中，however常修饰形容词或副词，从句的
结构是however＋adj./ad v.＋其他成分。
However hard she tried，she could not change his mind.

4．as引导让步状语从句时，通常放在句首，而且 要倒装，如果从句中单数名词
作表语，倒装时该名词前不加冠词。结构为：adj./adv./n.＋ as＋主语＋谓语。
Unlikely as it may sound，what I’m telling you is true.
Girl as Mary is，she is as brave as a boy.