I won't lend you the book before I have finished it.为什么用have fini_英语解答

I won't lend you the book before I have finished it.
为什么用have finished

人气：483 ℃　时间：2019-09-26 14:33:38

解答

有 before 或 after 的句子,用完成时态或一般时态都可,无太大区别.这句用
before I finish it
也对.