Thehouse____acrosstheriverwillbetheteachers'dormitorywhencompleted
A.builtB.beingbuiltC.buildingD.havingbuilt
房子被造,那为什么要变成ing啊?bebuilt不可以嘛?还有句中theriver后面怎么可以加willbe起到什么作用?这句句子的结构是什么啊?非常困惑.