问题补充：
It is demanded that the plan out as soon as possible.
A. must be carried
B. is to carry out
C. carried
D. be carried
答案：
A. must be carried
B. is to carry out
C. carried
(答案→)D. be carried
解析：本题重在理解虚拟语气的运用。常见动词：一个坚持，两个命令，三个建议，四个要求。即:
1. insist 2. order, command 3. advise, (sb. ) suggest, propose 4. demand , require, request, desire
这些动词后面的宾语从句要使用虚拟语气。即从句中的动词使用should + 动词原形，或者将should省略。故选D。
