英语词组：A是B的2倍长

至少三种最常见的表达方式

A is twice of B in length.
A is twice as long as B
A is twice the length of B.
A is as long as twice the length of B.
Length of A doubles that of B.
A is of twice the length of B.
Length of A is the double of B.
A has double length of B.
A has a length of the twice of B.
A has the duplex length of B.
A is of the twofold length of B.
A is 100% longer than B.
B is a half of A in length.
B is 50% shorter than A.
...

注：twice、double、triple 最常用于口语中，在数理化表达中可用 two times、200%、three times 这些替换使用，意思相同。

is 可以用 equals 、has 等替换，twice 和 100% 可以在颠倒主谓语后以 a half 和 50% 替代。作为数理语言，实际表达方式可以有近乎无数种组合，没有对错，只有好坏、简练与否的区别。

注意，在使用longer than这种表达法时，必须注意倍数使用正确。譬如：A is 2 times （或 200%）longer than B 意味着A是B的3倍长！

最后，注意虽然有这么多的表达法，但并不代表任何表达都是对的！这里出现了不少病句。例如：A is B's double long 是错的，因为long 不是名词。A's length is double longer than B 也是错的，因为double不能像twice那样作副词使用。

A is B's double long. A's length is double longer than B. A is 2 times longer than B.

你是上课不好好听讲吧.... A is 2 times longer than B A is 2 times the length of B A is 2 times as long as B The length of A is 2 times of B

正确的应该是: A is twice as long as B. A is twice longer than B. A is twice the length of B.

A is twice as long as B. A is twice longer than B. the Length of A doubles that of B

面积=长x宽

则a的面积/b的面积=（a的长xa的宽）/（b的长xb的宽）

    =(a的长/b的长)x(a的宽/b的宽）

    =2x3

    =6

所以a的面积是b的  6倍.