7 形容詞與副詞的比較級
    大多數(shù)形容詞（性質(zhì)形容詞）和副詞有比較級和級的變化，即原級、比較級和級，用來表示事物的等級差別。原級即形容詞的原形，比較級和級有規(guī)則變化和不規(guī)則變化兩種。
    1） 規(guī)則變化
    單音節(jié)詞和少數(shù)雙音節(jié)詞，加詞尾-er，-est來構(gòu)成比較級和級。
    8 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)+ that + 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.
    9 比較級形容詞或副詞 + than
    You are taller than I.
    注意： 1）要避免重復使用比較級。
    （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 than any country in Asia.
    （對） China is larger than any other countries in Asia.
    3）要注意對應句型，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。
    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.
    典型例題
    1）The weather in China is different from____.
    A. in America　 B. one in America
    C. America D. that in America
    答案：D.
    2）After the new technique was introduced，the factory produced ___ tractors in 1988 as the year before.
    A. as twice many　　B. as many twice
    C. twice as many　D. twice many as
    C. 此句意為“這個廠1988能生產(chǎn)的拖拉機是往年的兩倍”。 表示倍數(shù)用“倍數(shù)+ as + 形容詞原形+ as +比較對象”的句型。所以此句答案為C。
    This ruler is three times as long as that one.