1.secret services 特务机关

例句:Our secret services and our navy are completely incompetent.
我们的特工处以及我们的海军都无能之极。

2.at the time 当时，在那时

例句:I was not in Britain at the time.
当时我不在英国。

3.key witness 关键证人

例句:He is expected to be the key witness at the trial.
他将成为审判的关键证人。

4.tip off 透露消息；泄露

例句:The police arrested him after an anonymous tip off.
在接到匿名举报后，警方逮捕了他。