He had no sooner finished his speech ________ the students started cheering.[ ]

A. since  

B. as

C. when  

D. than

患者，男，60岁。慢性支气管炎病史20年，肺心病病史5年。近1周感冒后咳嗽，吐黄痰，心悸气短加重。下列哪项治疗原则是最重要的（）

A.止咳

B.祛痰

C.抗感染

D.强心

E.利尿