正弦波脉宽调制的英文缩写是()
A.PID
B.PWM
C.SPWM
D.PD
参考答案:C
We are not fighting for ______, but for ______. [ ]
A. the food and wealth; the peace
B. food and wealth; peace
C. the food and the wealth; peace
D. food and for wealth; the peace
—"Do you want an apple, a banana or a pear?"
—_____. They all look bad." [ ]
A. Both
B. None
C. All
D. No one.