I would like to keep in contact.

我希望保持联系。

I will keep in contact with you.

我将会在与你的接触中保存。

We must keep in contact with them.

我们必须和他们保持联络。

You should keep in contact with him.

你应该与他保持联系。

Remember to keep in contact with me by phone.

记住要与我保持电话联系。