问题补充:
They received demands that the work at once.
A. must be done
B. would be done
C. had been done
D. be done
答案:
A. must be done
B. would be done
C. had been done
(答案→)D. be done
解析:考察虚拟语气。名词demand后面的同位语从句中要使用虚拟语气,使用should+动词原形;should可以省略。句意:他们收到这个命令,这份工作要立刻被做。故D正确。