the children are required not to leave the building unless.to do so

问题描述:

the children are required not to leave the building unless.to do so
A being told B they will be told C be told D told 详细解释一下吧 谢谢!

英语人士也喜欢省略啊.一楼的答案是对的.就是看不出来啊 以后遇到句子该怎么判断呢~?“are required” not to leave the building unless “are told”打引号的用法类似。记住它的形式就不会错了以后。