电源是把___________能转化成__________能的装置.干电池在供电时,__________能转化成__________能。
其它形式的;电;化学;电
Miss Li _____ as a secretary for five years in the company, and now she is general manager of it.[ ]
A. has served
B. had served
C. served
D. serves
道德评价有哪两种基本形式?