After studying in a medical college for five years, Jane     her job as a doctor

in the countryside.

A．set out

B．took over

C．took up

D．set up

ZDll5型换向器有（）换向片，其横截面积为梯形，升高片与换向片之间采用银焊片焊接。

A、341片

B、372片

C、412片

D、431片