twice的詞性和用法

例句：

1、We go there maybe once or twice a month.

我們每月大概去那裏一到兩次。

2、You should visit your dentist at least twice a year.

你應該每年至少去看兩次牙科醫生。

3、New drivers have twice as many accidents as experienced drivers.

新駕駛員所出的`事故是老駕駛員的兩倍。

4、You should think twice about employing someone you've never met.

僱用素不相識的人應三思而行。