所有的主从复合句,主从句的时态都得一致。 一致并不意味着时态完全一样,只要从时间关系上讲得通即可。
用as soon as 引导时间从句时要注意"主将从现”即从句用一般现在时表将来。
如:I'll tell him about the news as soon as I see him.
as用作副词:
第一种是用在“as+(形容词或副词)+as”中,其中第一个as为副词(例句见上, as分别修饰形容词tall和副词long)
第二种表示以特定形式或关系考虑——通常用在介词或分词前
The ‘h’ in honest is silent, as in ‘hour’. honest中的h与hour中的h一样都不发音。
my opinion as distinguished from his:我的意见与他的不同
As always, he said little. 他和平时一样,少言寡语。
第三种表示举例:various trees, as oak or pine(同such as)
as用作代词(关系代词):
(a) 关系代词as引导限定性定语从句:一般用于以下固定结构中:
1. 用于the same…as结构中,例如:
This the same book as I read last week.
2. 用于such…as结构中
I don’t like such books as he recommends.
3. 用于“so+ adj +a/an +n + as”结构中
I am not so strong a man as I was.
即:当先行词含same、 such、so等时,关系代词要用as。
(b) 关系代词as引导非限定性定语从句:先行词是一个句子或短语:
As is often the case, she is late. (放在句首,先行词是整个句子she is late)
He is very careful, as his work shows. (放在句末,先行词是整个句子he is very careful)