I tracked down the printer who did the original我找到了最初印請帖的印刷商

track down:跟蹤追捕； 追查

It took the police several days to track down their quarry.

警方用了幾天時間追查到案中目標。

I finally track down the reference in a dictionary of quotation.

我終於在引語詞典中查到了那段引文。

Must have slipped her mind.她肯定是忘了

slip one's mind:忘記

He was supposed to have brought home a loaf of bread, but it slipped his mind.

他本來想帶一條面包回家的，可他把這事給忘了。

常用短語:

slip up失誤

slip away逃走

He can catch up.他待會就來

catch up:趕上

She walked too slowly to catch up with us.

她走得太慢，跟不上我們。