1)在否定句或疑问句中可用so as。
He cannot run so/as fast as you.
2)当as as 中间有名词时采用以下格式。
as +形容词+ a +单数名词
as + many/much +名词
This is as good an example as the other is.
I can carry as much paper as you can..
3)用表示倍数的词或其他程度副词做修饰语时，放在as的前面。
This room is twice as big as that one.
Your room is the same size as mine.
4) 倍数+ as + adj. + as 倍数+ then + of
This bridge is three times as long as that one.
This bridge is three times the length of that one.
Your room is twice as large as mine.
Your room is twice the size of mine.