用于两者之间的同级比较，表示"…和…一样"：
① "as +原级形容词+as"的结构，表示前后两者的情况一样
"A+系动词+as+形容词原级+as+ B，
eg. Bill is as funny as his father.
My handwriting is as beautiful as yours. 我的书法和你的一样好。
"A+谓语动词+as+副词原级+as+ B"
eg. Lucy speaks Chinese as well as Lily.
② 在否定句中，用"not as/ so +原级形容词as"结构，表示前者不如后者。
"A+系动词+not as/so+形容词原级+as十B"
eg. These books aren't as interesting as those.
I am not as/ so busy as I used to be. 我没有过去那么忙了。
"A+助动词/情态动词+not+谓语动词+as/so+ B"
eg. She didn't sing so well that night as she usually does.
③ 如若第一个as/ so后的形容词作定语修饰名词，应将该名词及有关修饰语都放在第一个as/ so之后。
We have produced as many tractors as we did last year. 我们生产的拖拉机和去年一样多。
I don't make as/ so much money as you do. 我挣得钱不如你挣得多。