im sure he will be back [ ] [ safe] soon

im sure he will be back [ ] [ safe] soon how soon will he be back对吗 I’m sure that he will be back in ____. I think he will be back soon的同义句 l think he will be back soon.为什么不能写成 l think he will back so i will be back soon I am not sure wether he will come back soon?whether引导的是什么从句? 他很快就会回来的 He will be back soon He will be back quickly .都可以吗 i am sure he---- (be) happy soon 请说明原因He ---- for two months.I hope he will be back soon.A.ha Where is your father now?He is [].He will be back soon.Pieas ----How soon will he come back?