as...as 表示"和……一样"，中间用形容词或副词原级；否定形式为 not as/so...as（不如……）。
要点讲解
- 肯定结构：as + 原级 + as：He is as tall as me. 他和我一样高。
- 否定结构：not as/so + 原级 + as：This book is not as interesting as that one. 这本书不如那本有趣。
- 倍数 + as...as：This room is twice as big as that one. 这个房间是那个的两倍大。
- as...as possible = as...as sb. can：as soon as possible 尽快。
- 固定搭配：as soon as 一……就……；as long as 只要。
经典例句
- She sings as well as her sister.
她唱得和她姐姐一样好。 - Tom is not so careful as Jim.
汤姆不如吉姆细心。 - Please come as early as possible.
请尽早来。
易错提醒
- as...as 中间必须用原级，不能用比较级；否定句中 so 与 as 可互换。