there used to be a tall tree in front of our classroom,_____?改为反义疑问句
问题描述:
there used to be a tall tree in front of our classroom,_____?改为反义疑问句
是wasn't there 还是didn't there?
答
usedn't there
这个问题一直有歧义,网上搜搜,上面写的很详细