含有蒽醌的中草药是
A．大黄B．薯蓣C．洋地黄D．人参E．黄连
参考答案：A
—Mr. Wang __________ be in the office. The light is still on.
—No, he __________ be. Because he phoned me from the farm just now.
A．may; mustn’t
B．mustn’t; mustn’t
C．can’t; can’t
D．must; can’t
分别简述井控设备拆卸、试压作业风险控制措施？
