在调频电台电路中预加重是（）网络，用于发射机。
A.微分
B.积分
C.高频
D.模拟
参考答案：A
What ___ you____ at ten yesterday evening?
A．have, done
B．did ,do
C．were doing
D．will do
You can _____some honey _____the milk. That mixture can make your skin much whiter and healthier. [ ]
A. add; /
B. add; into
C. add; to
D. add up to;/
