1. at one time 曾经；一度
例句：Most of us, at one time or another, have been struck with the thought that we might mistake a dream for reality, or reality for a dream.
我们中的大多数都曾经有过这么一种想法：我们可能将一个梦境误认为是现实，或者将现实误认为是梦境16[Cew;mG40p!XX6#Q。

2. key pal 笔友，网友
例句：I have an English- speaking key pal now, and she points out my grammar mistakes.
现在我有了一位英文笔友，她会指出我在文法上所犯的错误RWpdi+EuZ(yR;iQ#@,。

3. strike up 建立起（友谊）
例句：The two strike up a unique friendship, even as a string of murders in their small town threaten to tear them apart.
尽管小镇上发生的一连串谋杀可能让他们分开，两人仍然建立起一段特殊的友谊#[LIs]R;J~]U&#gbr3。

4. keep in contact 保持联系
例句：She says its success is down to the simple action of establishing an "e-group" for journalists, enabling them to keep in contact, discuss issues and exchange articles.
她说它的成功归功于建立一个记者的“网群”的简单行动，这让他们可以保持联系，讨论问题并交换文章[%c;^s-(5_tA1.dr)。