Passage Two
Questions 29 to 31 are based on the passage you have just heard.

A．They often ride a motorcycle.

B．They used to ride a horse.

C．They work in the mountains of Canada.

D．They ride a horse.

非甾体抗炎药是通过抑制以下哪个介质的产生而起到镇痛、解热、消肿的作用（）

A.T淋巴细胞

B.免疫复合物

C.白介素-1

D.前列腺素

E.肿瘤坏死因子-α