问题补充:
The message is very important, so it is supposed as soon as possible.
A. to be sent
B. to send
C. being sent
D. sending
答案:
(答案→)A. to be sent
B. to send
C. being sent
D. sending
解析:考察固定结构和语态。Be supposed to do sth应该做某事;根据句意可知使用被动语态。句意:那个消息非常重要,所以它应该尽快被发送。