请教英语问题在线等it is going to rain,将要下雨,为啥不能表达成 it is raining ,进行时

It is going to rain tomorrow.换个方式表达 what is the weather going to be?it's________A raining B rain It's going to (raining,rain) it must rain 与 it is going to rain 区别 There is ( ) rain.It is raining ( ) now. It___that it is going to rain tomorrow It (is going to/will) rain. It is going to _____ (rain). ——it is going to rain _____(恐怕)it is going to rain look at the clounds!it()Awill rain B is going to rain,为什么不能选 改错 It is going to rain .It is cloud now