two-way 双向的

We need a two-way switch. 我们需要一个双路开关。

He invented a two-way recorder. 他发明了两用收录机。

in twos 两个两个地

The children walked in twos with one teacher in front and one behind. 孩子们排成两行走，前后各有一位老师。

in twos and threes 三三两两地

Applications for the job are coming in slowly in twos and threes. 申请这份工作的信件三三两两来得很慢。

in two twos 立刻；一转眼

My pen was lost in two twos. 我的钢笔一转眼就不见了。

put two and two together 根据所见、所闻等推测出真相

He is rather inclined to put two and two together and make five. 他一推测就出圈儿。

They came to the conclusion that he hadn't run out of their city, putting two and two together. 根据事实推断，他们得出这样的结论，他还没有跑出这座城市。