double one’s income

使收入翻一番

As a matter of fact, the prices may double at Christmas time.

事实上，圣诞期间价格可能会上涨一倍。

The city was enclosed by walls of double thickness.

该城被两倍厚的墙围了起来。

a double room

双人间

a double meaning / purpose

双重意义/目的

Don’t park your car on double yellow lines.

不可以在双黄线处停车。

My name is Green with a double “e” and my phone number is two four double 2.

我叫格林，有两个e字母，我的电话号码是2422。

What is the double of five?

5的2倍是多少？

mixed doubles

男女混合双打

The famous player was the champion of both women’s singles and doubles.

该著名运动员曾经是女子单打和双打冠军。

Is that a single or a double you want?

你要的是单人间还是双人间？

She often sees double and can’t tell how far away things are.

她总是看重影，判断不出东西离她有多远。