I really have to be going.为什么要用be going而不直接说I really have to

I really have to be going.为什么要用be going而不直接说I really have to --Please excuse me ,but i really have to be going. I've really got to be going为什么用I've really got 排序 I'm going to visit Mars.Really?what areyou going to be in i am going to be sick为什么要用be? I really regret going to the movies last week为什么用going to i have a present be going to give you 英语翻译开头是dear diary,I thought today was going to be really bad 英语翻译sorry,it's my fault.Im going to be mess..i really want t 一道英语听力题M:I thought this book was going to be really boring.W be going to will have I really want to angry and be annoyed,but I feel have not al