可不可以说:When will she come?不加back 为什么?

可不可以说:When will she come?不加back 为什么? When will she come back? When will she come back IN和LATER区别I will come back in five days.可不可以说成I will come ba 可不可以说when will you reach olease call me when she comes 还是will come back为什么? when will you come back 为什么用back When I succeed,she will come back to me? When will you come back? When he will come back i wonder when mum (will come back).I think she (will come ba I hope you will come back soon.>句型不是hope to 为什么will前面不加to?