察觉出

How did you spot those fifties were counterfeited?

你怎样那些50元面值纸币是伪造?

I detected a faint note of weariness in his voice.

我从他声音中一丝倦意。

I can detect signs of improvement in your thinking.

我可以你思考题方面。

I soon discerned that the man was lying.

我很快便这个人是在撒谎。