PN结的最大特点是具有()。
A.导电性
B.绝缘性
C.单向导电性
参考答案:C
Mrs. Green wants to buy that kind of cloth because she___________ that the cloth__________ very well.
A.has been told; washes
B.is told; is washed
C.has been told; is washed
D.is told; is washed
下述主动脉病变在普通X线平片上的表现,错误的是()
A.主动脉增宽、伸长和迂曲
B.主动脉搏动增强
C.主动脉外形不规则
D.主动脉位置改变
E.主动脉狭小