Question

原因是因为这个星期天我们全家人都要去乡下看望我爷爷那天是他的80岁生日英语

Answer 1

原因是因为这个星期天我们全家人都要去乡下看望我爷爷，那天是他的80岁生日。
用英语表达：
The reason is that my whole family is going to visit my grandfather in the countryside this Sunday, which is his 80th birthday.
注：完全没有问题，希望帮助到您。请及时点击采纳。