光敏电阻的工作原理基于()。
A.光生伏特效应
B.光电导效应
C.二次电子释放效应
D.外光电效应
参考答案:B
________ operation was very successful indeed,which was ________ comfort to the concerned mother.
A.The;/
B.An;the
C.An;a
D.The;a
滚动轴承装配后,()将要增大,外圈将要缩小,所以装配间隙要比()小些。