__before we leave the day after tomorrow,we should have a wonderful party答案是were they to arrive 还有 Had they arrived Were they arriving Would they arrive一点这个倒装句的助词提前为什么是were是过去式 ,不是原形are 不是had或 did二点 to arrive arrived ariving arrive分别在什么情况下用
问题描述：
__before we leave the day after tomorrow,we should have a wonderful party
答案是were they to arrive 还有 Had they arrived Were they arriving Would they arrive
一点这个倒装句的助词提前为什么是were是过去式 ,不是原形are 不是had或 did
二点 to arrive arrived ariving arrive分别在什么情况下用
答