下述药物中属于祛痰药的包括（）

A.氨溴索

B.厄多司坦

C.羧甲司坦

D.溴己新

E.喷托维林

—You were out when I dropped in at your house.

—Oh, I ________ for a friend from England at the airport.

A．was waiting

B．had waited

C．am waiting

D．has waited