this offer is subject to your reply reaching us before june 30th

问题描述:

this offer is subject to your reply reaching us before june 30th
请问这句话怎么理解.
your reply reaching us 是不是一个时间状语还是时间定语,代表 when.可为什么用to 呢

这个报价在六月30日前收到你的回复前都有效.subject to是习惯用语.