【单选题】What will be the biggest problem with the big cities?
A.
There are no jobs to find and no place to live in.
B.
The newcomers stop coming in large numbers.
C.
Good doctors decide to move out of the cities.
【单选题】若地形点在图上的最大距离不能超过3cm,对于比例尺为1/500的地形图,相应地形在实地的最大距离应为
【单选题】With the introduction of the electronic computer, there are no complicated problem ______ can be solved.