1、一般现在时：I have to visit Mr Wang tomorrow.
明天我得去拜访王先生。
2、一般过去时：That night we had to walk home because there was no bus.
那天晚上我们不得不步行回家，因为没有公共汽车。
3、一般将来时：We'll have to ask Zhang Ming instead.
我们得请张明代替。
4、与may 连用：I think he may have to help his Dad in the garden.
我想他可能得在花园里帮他爸爸干活。
扩展资料：
have to 与 must 的用法区别
一、 have to 比较强调客观需要，而 must 着重说明主观看法。
1、 My mother is ill. I have to look after her at home.
妈妈病了，我得在家照看她。
2、 You must finish your homework first.
你必须先完成作业。
二、 have to 有时态和人称变化，而 must 则没有。
1、 Mary has to water the trees.
玛莉得浇树。
2、 He must bring a picnic tomorrow.
他明天得带野餐。