How long will it be ___ another power station can be built in our_英语解答

How long will it be ___ another power station can be built in our city
Abefore B when c after D as

人气：248 ℃　时间：2020-05-20 09:17:30

解答

A before
还有多长时间另外一个发电站将在我们城市建成?