直接的供应链涉及上下游产品流、服务流、资金流的（）企业、供应商和客户组成。
A.多个
B.几个
C.一个
D.无穷多个
参考答案：C
Let me_____your new sweater. [ ]
A. look
B. have a look at
C. have a look
D. have look at
过程模型
