判断电流磁场的方向是用（）。
A.右手定则
B.左手定则
C.安培定则
参考答案：A
She isn't here. She has to _____her baby at home. [ ]
A. look at
B. look like
C. look ater
D. look for
指数型证券组合只是一种模拟证券市场组合的证券组合。 ( )
