keep in mind 记住 不忘记

We must keep these lessons of history firmly in mind.我们应该牢记这些历史的教训。

keep on 继续

Why does the baby keep on crying?这个婴儿为什么不停地哭？

keep one's word 遵守诺言，守信

He never keeps his word.他从不信守诺言。

keep to 坚持，遵守，遵循

Keep to your task till you've finished.要坚持你的工作直到完成为止。

keep up with 与....同步，跟上

We must keep up with times.我们必须跟上时代。

knock down 击倒，撞倒

He knocked down the hottle with carelessness.他不小心撞倒了瓶子。