I'll have to be on my guard, you see, so I better start learning what I shouldn't do.

我得提高警惕，你知道，所以我最好开始了解我不应该做什么。

It was a comfort; but, indeed, I had been on my guard almost from the beginning of the interview.

这是一种安慰；但是，事实上，几乎从采访开始我就一直保持警惕。

The idea struck me that if she discovered I knew or suspected her guilt, she would be playing of some of her malignant pranks on me; I thought it advisable to be on my guard.

我突然想到，如果她发现我知道或怀疑她有罪，她就会对我开一些恶作剧；我认为保持警惕是明智的。