下图反映了欧洲中世纪的什么制度?
A.世袭制
B.封建等级制度
C.宗法制
D.军事奴隶制
答案:B
(江苏省南通市2009期末调研)Miss Li ______ as a secretary for five years in the company, and now she is general manager
of it.
A.serves
B.served
C.had served
D.has served
根据误差性质和特点,可以把测量误差分为()、系统误差和随机误差三大类。
A、较大误差
B、较小误差
C、粗大误差