倍数表达法有三种：

倍数＋原级

倍数＋比较级

倍数＋名词短语

1. three times as long as

2. three times longer than

3. three times the length of

再如：和---四倍一样宽

1. four times as wide as

2. three times wider than

3. three times the width of