As...意为“和...一样”，表示同级的比较。使用时要注意第a为副词，第二个as为连词。其基本结构为:as+adj/adv.+as。

例如: This film is as interesting as that one.这部电影和那部电影一样有趣。

Your pen writes as smoothly as mine.你的钢笔书写起来和我的一样流畅。

其否定式为 not as/so+adj/adv.+as。

例如: This dictionary is not as/so useful as you think.这本字典不如你想象的那样有用。

若有修饰成分，如 twice, thee times,ha, a quarter等，则须置于第一个as之前。

例如: Your bag is twice as expensive as mine.你的袋子比我的贵一倍

几个关于as.as的常见句型

（1）as. as possible

Please answer my question as soon as possible.请尽快回答我的问题。

（2）as.as usual/before

She looks as pretty as before.她看起来和以前一样漂亮。

（3） as long as(引导条件状语从句)

It took us as long as three years to carry out the plan.我们花了长达三年的时间才完成这项计划。

（4）as far as

He walked as far as the railway station yesterday evening.昨天傍晚，他一直散步到火车站。

（5）as well as

She cooks as well as her mother does.她烧菜烧得跟她母亲一样好。

一些带有as...as结构的常见短语归纳：

as busy as a bee. 像蜜蜂一样忙碌。

as easy as ABC. 像ABC一样容易。

as deep as a well. 像井一样深。

as light as a feather. 像羽毛一样轻。

as soft as butter. 像黄油一样软。

as rich as a Jew. 像犹太人一样富裕。