---- It is demanded that the letter by the end of this week , dad !
----I’ll do it immediately .
A. should mail
B. was mailed
C. mailed
D. be mailed
网友回答
A. should mail
B. was mailed
C. mailed
(答案→)D. be mailed
解析：考查虚拟语气。在demand后从句中要求用should +动词原形表示虚拟语气，should可以省略，故选D。