【题目】It will be very convenient to travel in this city when the underground ________ next year.
A.will be completed
B.is completed
C.has completed
D.would complete

【答案】B
【解析】句意：当这条地铁明年完工之后，在这个城市旅行将非常方便。主句是一般将来时态，所以后面when引导的时间状语从句用一般现在时态；underground和complete之间是被动关系，故用一般现在时态的被动语态。故选B。