()是保证人和债权人约定当债务人不履行债务时,保证人按照约定履行债务或者承担债务的行为。
A.保证
B.抵押
C.质押
D.留置
参考答案:A
— Do you have any plans for the winter holiday?
— Since you are crazy about music, why not go to some ________ concerts?
A.lively
B.live
C.alive
D.living
精的失常主要包括()和()两方面。