check up on: 检查，调查
But check up on him from time to time.
不过有时间的时候去看看他。
Consumers often find it difficult to check up on any of the claims made by the salesmen.
顾客常常发现很难核对推销员所声称的功能。

speak of the devil: 说曹操曹操就到
Speak of the devil and it will appear.
说曹操，曹操就到。
Speak of the devil, here she comes now.
说曹操曹操到，她现在来了。

in a tight spot: 身处困境
She'll always help if you're in a tight spot.
你有困难，她总会帮忙的。
He hasn't done any review and there are only two days left so he's in a tight spot with his exams.
他一点都没复习，只剩两天了，他可得为考试为难了。

take the lead: 领导
Active fiscal policy will soon take the lead in stimulating the economy.
积极财政政策很快将在刺激经济方面发挥带头作用。