Never get on or off a bus while it is moving.

公共汽车没停稳时千万不要上下车。

Would you look after the children while I do the shopping?

我买东西的时候你能不能照看一下孩子？

I hurt my leg while playing football.

我踢足球时把腿弄伤了。

I was never very neat, while my roommate Kate was extremely organized.

我从来不是一个很爱整洁的人，而我的室友凯特却极有条理。

While online shopping has changed our life, not all of its effects have been positive.

尽管网上购物已经改变了我们的生活，但并非它所有的影响都是正面的。

While there’s life there’s hope.

只要活着就有希望。

once in a while

偶尔；间或

Would you like to come in and rest for a while?

你要不要进来休息一会儿？

The file may take a short while to download.

下载这个文件可能需要点儿时间。