网上中介型B2B
参考答案：
网上中介型企业间电子商务是指企业利用第三方提供的电子商务服务平台实现企业与客户或者供应商之间的交易。
椅高
24. Only when the meeting began _______ that he had left his papers at his office.
A．will he realize
B．he did realize
C．did he realize
D．should he realize
