Itisbelievedthatanewkindofdrug

问题详情：

It is believed that a new kind of drug _____ by the scientists and they are hopeful that they will succeed in a few months.

A. has been developed                 B. is being developed

C. is developing                        D. has developed

【回答】

B

知识点：现在进行时及其被动式

题型：选择题