as + 形容詞或副詞原級 + as
    1）在否定句或疑問句中可用so… as.
    He cannot run so/as fast as you.
    2）當(dāng)as… as 中間有名詞時采用以下格式。
    as +形容詞+ a +單數(shù)名詞
    as + many/much +名詞
    This is as good an example as the other is.
    I can carry as much paper as you can……
    3）用表示倍數(shù)的詞或其他程度副詞做修飾語時，放在as的前面。
    This room is twice as big as that one.
    Your room is the same size as mine.
    4）倍數(shù)+ as + adj. + as　<=> 倍數(shù)+ 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.
    比較級形容詞或副詞 + than
    You are taller than I.
    They lights in your room are as bright as those in mine.
    注意：
    1）要避免重復(fù)使用比較級。
    （錯）He is more cleverer than his brother.
    （對）He is more clever than his brother.
    （對）He is clever than his brother.
    2）要避免將主語含在比較對象中。
    （錯）China is larger that any country in Asia.
    （對）China is larger than any other countries in Asia.
    3）要注意對應(yīng)句型，遵循前后一致的原則。
    The population of Shanghai is larger than that of Beijing.
    It is easier to make a plan than to carry it out.
    4）要注意冠詞的使用，后有名詞的時候，前面才有可能有名詞。
    比較：
    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