He was wondering whether to go home or stay at school.
2.引导主语从句(包括从句在句首的位置)应当用whether,不用if,如:
Whether it is true remains a problem.
Whether he can stay with us is another matter.
Whether he will come, I am not sure.
Whether or not he did it, I cannot tell.
3.引导表语从句用whether,不用if,如:
The question is whether you should accept it.
The question is whether he will speak at the meeting.
4.引导同位语从句用whether,不用if,如:
The question whether he’ll attend the meeting is essential.
I am in doubt whether I should agree to the plan.
二、whether 还可以引导让步状语从句,意为“不管;无论”;而if则不能引导这种从句,如:
I shall tell her about it whether you agree or not.
Whether or not the figures are accurate, we have to recheck them.
Whether or not we had a baby, we could not survive just on my salary.
三、if还可以引导条件状语从句,意为“如果;假如”,而whether则不能引导这种从句,如:
We shall do this experiment if we have time.
四、如果在从句中使用if表示“是否”容易与表示条件的状语从句混淆时,应注意避免使用if,例如:Please let us know if they are coming. 这句话可以理解为“如果他们要来,请通知我们一下。”也可以理解为“请告诉我们,他们是否要来。”若表示后一层意思,应当使用,以免引起误会。