as+形容詞/副詞+as或as+形容詞+名詞+as。固定用法“as...as possible”意為“盡可能地...”,例如“as quicky as possible盡可能地快”，“as much as possible 盡可能地多”，“as carefully as possible 盡可能地小心”等等。

1.as...as結構的基本意思是“與……一樣”，其中接形容詞或副詞的原級，在否定句中，第一個as也可換成so。如：

He doesn't study as/so hard as his brother. 他學習不如他弟弟努力。

2.若涉及數量或程度，可用“as much+不可數名詞+as”和“as many+可數名詞復數+as”。如：

He doesn’t pay as much tax as we do / as us.他沒我們交的稅款多。

There are not as many restaurants as there were.現在餐館沒有過去多了。

3.as...as接形容詞時，有時該形容詞還可修飾另一名詞，但這個名詞應帶有不定冠詞（注意詞序）。如：

I have as good a voice as you.我的聲音和你一樣好。