He hasn't shown his face for a long time.

She makes an effort to learn German.

The thing-in-itself is a central concept for Kant in his philosophy.

In his youth, he wanted to sow his wild oats.

In this situation, he was on his own.

I have to rack my brain to find a solution.

She must pluck up courage and tell him the truth.

If you eat too much ice cream, you will upset your stomach.

It's late, I should clear off.

The trail of the criminal seemed to vanish into thin air.