题目

–Listen! Helen is singing in the next room.   -- It      be Helen. She has gone to Guangzhou.    A. would                  B. can’t    C. could                   D. might 答案：BShanghai is the first city in the world ____a high-speed maglev train, from the city to Pudong Airport. A、to build       B、to be built  C、to have built       D、to have been built