Some people feel easy and comfortable to be served by others but when they are asked to serve others ______, they are unwilling or even hate to do so.

A．in turn

B．in their turns

C．in their turn

D．by their turn

确定进货目标的内容包括掌握货物的到达（）

A、日期

B、日期、规格

C、日期、规格、数量

D、日期、品种、数量