Don't count on it.

别指望了。

You want to get your money back? Don't count on it.
你想把钱拿回去？别指望了

be firm in one's opinion

坚持己见

When you speak to him, be firm in your opinions.
你跟他说话的时候，要坚持己见。

do no good

没用，没有好处，do good to...表示"对某事有帮助"

Yelling at me will do you no good.
大声吼我对你没好处。

Definition: To stay too long as a guest; to annoy one's host or benefactor.
Example: 1) You should find your own apartment before you wear out your welcome at your sister's place.

2) Uncle Bob is wearing out his welcome here. Yesterday he left his clothes all over the floor, and today he broke the TV set.
Etymology: When a guest arrives, the host says "Welcome." But if a guest stays too long, the welcome will 'wear out' or fall apart from too much use.