(1)基本用法
该结构的基本意思是“与……一样”，其中接形容词或副词的原级，在否定句中，第一个 as 也可换成 so。如：
He doesn't study as [so] hard as his brother、 他学习不如他弟弟努力。
(2)涉及数量或程度的用法
若涉及数量或程度，可用“as much+不可数名词+as”和“as many+可数名词复数+as”。如：
He doesn’t pay as much tax as we do / as us、 他没我们交的税款多。
There are not as many restaurants as there were、 现在餐馆没有过去多了。
(3)有关词序的一点说明
其间接形容词时，有时该形容词还可修饰另一名词，但这个名词应带有不定冠词(注意词序)。如：
I have as good a voice as you、 我的声音和你一样好。
(4) 该结构的修饰语
根据情况可用(not) nearly, almost, just, nothing like, exactly, not quite, half, one-ten, twice, three times, 30 per cent等修饰，并且这些修饰语必须置于第一个as之前，而不能置于其后。如：
This room is twice as large as that one、 这个房间是那个房间的两个大。
You’re not half as clever us you think you are、 你远不是自己想像的那么聪明。
It took three times as long as I had expected、 这件事比我预料的多花了两倍的时间。