你应该在红灯时停车。

You ___should stop at a red light.

明天可能会下雨，你最好带把伞。

It ___should rain tomorrow, so you'd better bring an umbrella.

我应该什么时候开始准备考试？

When ___should I start preparing for the exam?

如果你需要任何建议，随时联系我。

If you ___should need any advice, feel free to contact me.