【单选题】关于 N 型半导体的下列说法,正确的是 _
B.
在二极管中, N 型半导体一侧接出引线后,是二极管的正极
C.
在纯净的硅衬底上,分散三价元素,可形成 N 型半导体
D.
在 PNP 型的晶体管中,基区正是由 N 型半导体构成
【判断题】同一企业生产、进口同一品种危险化学品的,按照生产企业进行一次登记,但应当提交进口危险化学品的有关信息。
【判断题】(取钱)Mature means reaching the end of its term and hands become payable.对
【单选题】By 'good sense' the writer means ______.
A.
the driver's ability to understand and react reasonably
B.
the driver's prompt response to difficult and severe conditions
C.
the driver's tolerance of rude or even savage behavior
D.
the driver's acknowledgment of politeness and regulations
【单选题】《危险化学品登记管理办法》规定:同一企业生产、进口同一品种危险化学品的,(),并提交进口危险化学品的有关信息。
【单选题】The underlined word 'land' in the first paragraph means__________ .
【单选题】The phrase 'evokes a sense of place' underlined in Paragraph 4 means to ______ .
A.
make readers think of a place.
B.
call up memories of nice things to readers.
C.
remind readers of important places.
D.
give readers the feeling of large areas.
【判断题】(取钱)mature means reaching the end of its term and hands become payable.对
【单选题】关于半导体,下列说法正确的是( )
B.
在硅或锗材料中掺入 5 价元素可形成 P 型半导体
D.
把一块 P 型半导体和一块 N 型半导体放在一起就会形成 PN 结