They often do some shopping on weekends.       [ ]

A. sell things    

B. work in the shop

C. buy things    

D. have meals in the shop

电磁感应现象揭示了电与磁之间的内在联系，根据这一发现，发明了许多电器设备。以下电器中，哪些利用了电磁感应原理 (      )

A．变压器

B．白炽灯泡

C．发电机

D．电吹风