光隔离器依据()工作。
参考答案:法拉第旋转效应
The money collected should be made good use _____ the people who suffered great losses in the earthquake.
A.of to help
B.to help
C.of helping
D.to helping
垄断竞争厂商长期均衡时,不但要求MR=LMC,而且要求()
A.P=LAC
B.P>LAC
C.P<LAC