某类物业管理服务由于需求、供给以外因素带来需求减少、供给也减少时,一定会出现( )。
A.均衡价格上升
B.均衡数量增加
C.均衡价格下降
D.均衡数量减少
参考答案:D
Ann is so careful that she always goes over her exercises to _______ there are no mistakes.
A.look for
B.make sure
C.find out
D.think about
简述使用游标的四个步骤。