在额定功率因数下,电压偏离额定值()范围内,且频率偏离额定值±2%范围内,发电机能连续输出额定功率。
A、±5%;
B、±8%;
C、±10%;
D、±12%。
参考答案:A
如图,AB、CD是同一光源S发出的经过平面镜MN反射后的两条光线,请找出S点的位置,并完成光路.
During the next ten years we both worked day and night to
_____ the money we had borrowed.
A.pay off
B.pay for
C.pay to
D.pay back