题目内容：

Jim's sister was badly ill ,so he had to ------ his home at once.
A.arrived in B.set off C.leave for D.go back 请选择并说明

优质解答

答案是C 啦,他必须立刻离开回家去.
have to do something,所以,to 后面跟的动词应该是原型；
如果选择 go back,应该是go back home,home 前不应该有his作修饰.
set off 按常理也说不通嘛!