下列化合物中，既能产生顺反异构，又能产生旋光异构的是：
参考答案：B
Are we going sightseeing sometime next month?-- No. The plan ______ at the second meeting.[ ]
A. was cancelled
B. would cancel
C. has cancelled
D. had been cancelled
工厂制度对管理提出的客观要求？
