倍数

　　1.用…times表示。如：

　　My room is three times as large as yours.

　　我的房间是你的三倍大小。

　　2.如果表示“是……两倍数”，一般用twice。如：

　　My room is twice as large as yours.

　　我的房间是你的两倍大小。

　　用-fold表示。如：

　　The value of the stock has increased two-fold since we bought it .

　　股票的价值已涨至我们购买时候的两倍。

　　3.用%表示。如：

　　The collection of our school library is 200% up compared with 1998.

　　我们学校图书馆藏书量与1998年相比增长了一倍.

　　4.用double(翻一番)，triple(三倍于)，again等词表示倍数。如：

　　This coat cost me as much again as the coat I have just bought.

　　这件外套花了我刚刚买的这件大衣价格的一倍

　　1)倍数+形容词/副词比较级+than

　　例如 The girl is ten times cleverer than her brother.

　　2)倍数+as+形容词/副词/(名词)+as

　　例如 His apartment is three times as large as that of mine. Americans eat( )as they actually need every day. (CET-4 1998,6) A) twice as much protein B) twice protein as much twice C) twice protein as much D) protein as twice much本题考查倍数的表达方法，正确形式应为：倍数+as+形容词/副词/(名词)+as，故答案为A.

　　3)倍数+名词

　　[例如 The sun is many times the size of the moon.

　　4)动词+倍数

　　例如 The pants have shortened two times since they were bought.

　　5)动词+by+数词/百分比/倍数

　　例如 The landlord wanted to raise the rent by a third. Between 1974 and 1997, the number of overseas visitors expanded ( )27%. (CET-4 2000,1) A) by B) for C) to D) in (A)