客户需求主要源于哪些方面（）。
A.市场需求
B.竞争需求
C.技术需求
D.法律需求
参考答案：A, B, C, D
—Time is limited. I have to finish this tonight.
—But it’s midnight now and you should have a sleep ______ much work you have to do.
A．however
B．no matter
C．although
D．whatever
斗轮堆取料机有（）和（）两种取料作业法。
