二、 as作关系代词,引导定语从句,作"正如"、"这一点"解。如:

He is very careful, as his work shows.

As is well-known, Taiwan belongs to China.

as的这种用法,请看2001年的高考题:

is known to everybody, the moon travels round the earth once every month.

A. It B. As C. That D. What

(字母下划横线的为正确答案)

另外,当先行词被the same, such等词修饰时,常用as来引导定语从句。如:

Such a clever boy as he can learn anything quickly.

I was reading the same book as he bought yesterday.