Perhaps everyone will live in vertical cities -high rises( ▲ )are so large that they can construct all the necessities o
问题描述：
Perhaps everyone will live in vertical cities -high rises( ▲ )are so large that they can construct all the necessities of life.A.that B.they C.where D.who请问该选择哪个?为什么?（选在上面括号里）
答
先行词,-high rises,定语从句are large,这个定语从句中缺主语,用关系代词,that 或which