小明通过互联网购买了一双名牌运动鞋，付款后试穿发现质量存在问题，属伪劣产品。这时，他可采取的正确做法是[     ]

①与网购公司有关人员协商解决

②向有关部门投诉

③请求消费者协会调解解决

④不去追究，另外购买一双

A．②③④

B．①②④

C．①③④

D．①②③

My sister met him in the hospital yesterday afternoon, so he _________ your lecture.

A． couldn’t have attended

B． needn’t have attended

C． mustn’t have attended

D． shouldn’t have attended