来源：学生作业帮 编辑：搜搜考试网作业帮 分类：英语作业 时间：2024/06/04 06:07:18
这句before后面从句时态的用法是怎么回事?
you must first establish the primary cause of waste generation before attempting to find solutions.
efore 后面的是you attempt to find solutions的省略形式.又如：Knock at the door before entering.=Knock at the door before you enter .
搜搜考试网