情态动词在英语中非常重要，它们用来表达说话人的态度、能力、许可、建议、义务等。以下是一些包含情态动词的句子和祈使句的例子：

能力

She can speak French very well.

I could play the piano when I was young.

请求

Can you pass the salt, please？

Would you mind opening the window？

许可

May I leave the room？

You mustn't smoke in here.

建议

You should eat more fruits and vegetables.

They might be coming to the party.

义务

We must finish our homework before we can go out.

You have to pay the bill.

禁止

You must not drive without a license.

It is not allowed to park here.

预测

It might rain later.

She will probably be late.

建议或责任

You should apologize for what you did.

You must take care of your health.

能力否定

I can't swim.

He can't swim either.

请求否定

Can you help me with this？

Would you please stop making noise？

许可否定

You mustn't smoke in the office.

You don't have to come if you're busy.

建议否定

You shouldn't smoke so much.

They shouldn't have left the house so early.

义务否定

You don't have to do that.

You mustn't ignore the rules.

禁止否定

You must not park here.

You must not lie to me.

预测否定

It probably won't snow this winter.

She might not be at home.

建议或责任否定

You shouldn't have done that.

You must take responsibility for your actions.

这些例子展示了情态动词在英语中的多种用法，包括表达能力、请求、许可、建议、义务、禁止、预测等。掌握这些情态动词将有助于更准确地表达思想和意图。