原级比较：as … as
同级比较用 as … as，中间必须用原级。
as + 形容词 / 副词原级 + as
要点
- as … as 表示「和……一样」，中间必须用原级。
- 否定形式：not as … as 或 not so … as。
- 中间也可以放「形容词 + a + 名词」：as good a book as。
- 表示倍数：twice as … as（是……的两倍）。
- as … as 中间也能塞「原级 + a / an + 单数名词」：He is as good a player as his brother.
- 比数量时用 as many + 可数复数 / as much + 不可数：I have as many books as you. / I do not have as much free time as you.
- 两条固定说法表"尽可能"：as … as possible 与 as … as sb. can，两者同义（as fast as we can = as fast as possible）。
- 倍数要放在第一个 as 前面：twice as old as / three times as long as（详见「倍数表达」）。
例句
He is as tall as his father.
他和他爸爸一样高。
She is as tall as her mother.
她和她妈妈一样高。
Mental health is as important as physical health.
心理健康和身体健康一样重要。
The way you speak matters as much as what you say.
你说话的方式和你说什么一样重要。
Please come here as early as you can.
请尽早到这里来。
This room is twice as big as that one.
这个房间是那个房间的两倍大。
易错提示
- as … as 中间用原级 —— 不能写成 as taller as。
- 否定句里第一个 as 可以换成 so：not so tall as。
- 看到 as taller as、as better as 这类直接判错 —— 两个 as 之间必须是原级。
- 否定式 not as / so … as 里 so 更口语、as 更书面，考试两个都收；但肯定句里只能用 as，不能说 so tall as。