1. You shouldn't smoke so much. It's harmful to your health.

2. You shouldn't be late for the meeting. It shows disrespect to your colleagues.

3. You shouldn't lie to your friends. It's not a honest way to treat them.

4. You shouldn't spend all your money on clothes. It's important to save some for the future.

5. You shouldn't drive without a license. It's against the law.

希望这些例句能帮助你理解"shouldn't"的用法。