I can detect signs of improvement in your thinking.

我可以你思考问题方面的进步。

How did you spot those fifties were counterfeited?

你怎样那些50元面值的纸币是伪造的?

I detected a faint note of weariness in his voice.

我从他的音中一丝倦意。

I soon discerned that the man was lying.

我很快便这个人是在撒。