你一定要小心开车。

You must be careful when you drive.

youdao

你一定要小心，不要理会鲍尔。

You must be very (careful) not to say anything to Paul.

youdao

记住，有些汽车不看红灯的。你一定要小心。

Remember, some cars don't stop for red lights. You always have to be careful.

youdao

Anyway, you have to be careful with your motorcycle and always wear your helmet.

不管怎么说，你都要小心骑摩托车，记得一定要带着头盔。

I didn't 实战 - SpeakingMax英语口语达人