留置作为一种担保方式，只能通过( )产生留置权。
A．合同约定
B．优先受偿
C．依法行使
D．财产转让
参考答案：C
--- Guess what! I have got A for my term paper.
--- Great! You ______ read widely and put a lot of work into it.
A．must
B．should
C．must have
D．should have
确定宴请时间应（）
A.根据上司的提议
B.避开客人的禁忌日
C.注意选择在重大的节日举行
D.考虑秘书本人是否能出席
