几道英语题，谢谢帮忙

来源：百度知道 编辑：UC知道 时间：2024/09/21 22:16:44
选词填空：have to/must/be allowed to/don't have to
I___go to bed early tonight.I'm so tired.
I___leave now.My sister is waiting for me.
You___smoke here beacause they sell petrol.
You___pay for that.It's free.

I have to go to bed early tonight.I'm so tired.
I must leave now. My sister is waiting for me.
You are not allowed to smoke here because they sell petrol.
You don't have to pay for that. It's free.
第三句好像有问题。。。