Relatives need time to grieve over loved ones they have lost.

亲属需要时间痛悼他们失去的至爱。

And you will grieve over that.

你也会伤心难过。

I grieve over my bad grade.

我悲叹自己的烂成绩。

Do not look back and grieve over the past.

不要回首过去，耿耿于怀。

It's a shame, but it's useless to grieve over that.

很遗憾，但也没必要过度伤心。