as + 形容词或副词原级 + as
　　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.

　　比较级形容词或副词 + than

　　You are taller than I.

　　They lights in your room are as bright as those in mine.

　　注意：

　　1）要避免重复使用比较级。

　　（错）He is more cleverer than his brother.

　　（对）He is more clever than his brother.

　　（对）He is clever than his brother.

　　2）要避免将主语含在比较对象中。

　　（错）China is larger that any country in Asia.

　　（对）China is larger than any other countries in Asia.

　　3）要注意对应句型，遵循前后一致的原则。

　　The population of Shanghai is larger than that of Beijing.

　　It is easier to make a plan than to carry it out.

　　4）要注意冠词的使用，后有名词的时候，前面才有可能有名词。

　　比较：

　　Which is large，Canada or Australia？

　　Which is the larger country，Canada or Australia？

　　She is taller than her two sisters.

　　She is the taller of the two sisters