You really must try and take more care.

你一定要更当心一点。

You're right.

你说得对。

Get to the heart of the matter.

请讲问题的实质。

At least we are not the only ones facing these problems.

至少不光是我们面临这样的问题。

Loosen up! it's not worth getting upset about.

放松点儿！ 不值得为这件事苦恼。

I'm afraid it just isn't good enough.

恐怕这不够好。