问题补充：
In order to produce more grain, itthat the area of farmland.
A. is demanded, being increased
B. has been demanded, be increased
C. demand, should be increased
D. demands, should increase
答案：
A. is demanded, being increased
(答案→)B. has been demanded, be increased
C. demand, should be increased
D. demands, should increase
解析：本题考查时态及虚拟语气。根据语境可知，那个地区已经被要求，故用现在完成时的被动语态，demand + that从句，用should + V原形，根据语境用被动，选B。
