进近时的飞机类别是按什么来分类的（）.
A.飞机的入口速度
B.飞机的失速速度
C.飞机的进场速度
参考答案：A
Have you ever felt your cheeks get hot，your palms sweaty or been afraid to _______your teachers’ eyes when they are about to call on someone?
A．take on
B．look into
C．occur to
D．look up
潜油电缆检修时直流耐压值为（）。
A.20kVDC/5min
B.15kVDC/5min
C.22kVDC/5min
D.14kVDC/5min
