倍数的表示

本文摘自复旦大学出版社《中学英语语法(高中第二版)》，作者魏孟勋

1、三倍以上的倍数

基数词 + times + as + 形容词或副词原级 + as
基数词 + times + 形容词或副词的比较级 + than
基数词 + times + the + 表示大小或数量的名词(size,length等) + of

This rope is three times as long as that one.
This rope is three times longer than that one.
This rope is three times the length of that one.

2、两倍的表示
表示两倍一般用twice。例如：
Our living room is twice as large as theirs.
Our living room is twice larger than theirs.
Our living room is twice the size of theirs.

double(作形容词或动词)可以表示两倍。例如：
His weight is double what it was ten years ago.
He has doubled his weight in the past ten years.

3、分数或百分数用于表示倍数的结构

The road is only half as wide as the newly built road.
The road is only half the width of the newly build road.

The pocket calculator is only one fourth the size of the old type.

I earn one third as much as he.

注意百分比多用与净增数。例如：
The number of college students in 1990 was 200% greater than in 1980.
We have produced 50 per cent more cotton than we did last year.