[英语]It's going to rain还是It will rain?

有区别,It's going to rain.表示“（有某种迹象）要下雨了.”； 而 It will rain.则不能表示有某种迹象,一般用于表示“（收音机或电视天气预报）将要下雨.”
如：Look at the black clouds.It's going to rain.
The radio says it will rain tomorrow.