英文中形容词有三个比较等级，因此，形容词有原级的用法、比较级的用法和最高级的用法。

1. 形容词的原级的用法主要是用于两者之间程度是否相同的比较。

2. 肯定形式用as+原级形容词+as+比较成分，表示“和...一样”。

Tom is as tall as I (am).

汤姆和我一样高。

And I am as fat as you (are).

而且我和你一样胖。

The temperature is as high as (it was) yesterday.

今天的温度和昨天一样高。

3. as much/many...+ as... 表示前后数量相同。

I had just as many bones as you did.

我和你吃的骨头一样多。

4. 否定形式用 not so (as)+原级形容词+as+比较成分，表示“不如...”。

Our hosts are not so nice as those of other dogs.

我们的主人不像其他狗的主人那样好。

Jane is not so (as) tall as I (am).

珍不如我高。

We don’t look so strong as that guy.

我们看起来没有那家伙壮。

5. as+形容词原级+as+用作比喻的名词，此结构形成了许多惯用语，多用于口语。

There! There! You are as hungry as a bear.

瞧！瞧！你饿得像只熊。

My God! It is as hard as a rock.

天啊！它硬得像块岩石。