as...as
as...as意为"和……一样",表示同级的比较.使用时要注意第一个as为副词,第二个as为连词.其基本结构为：as+ adj./ adv. +as.例如：
(1)This film is as interesting as that one.这部电影和那部电影一样有趣.
(2)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, three times, half, 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.
(4）还有一种情况是,举个例子：We spend as more time as we should on study.我们应该花更多的时间在学习上.
