I felt nervous because I was soon______(leave)home for the first _英语解答

I felt nervous because I was soon______(leave)home for the first time.
答案为什么是to leave?为什么不能是leaving?

人气：476 ℃　时间：2019-08-21 01:00:54

解答

be to do 表将来,但是过去进行时不能表将来.过去进行时可以表示将来的吧只能用现在进行时表将来。