在瓜皮表面刻出凹进去的线条花纹是（）。
A.阳文雕刻
B.阴文雕刻
C.花纹雕刻
D.镂空雕刻
参考答案：B
He was afraid what he had done ______ a disastrous effect on his career.
a. might have b. could be c. have been d. shall be
3000伏电气设备的最小间隙为（）毫米。
A.18
B.24
C.32
D.36
