We（）on this project for four hours. Let's have a rest.

A. are working

B. have been working

C. worked

D. had worked

关于川贝母、浙贝母的说法，正确的有（）。

A.均为治疗热痰、燥痰的常用药

B.均能散结消肿，用于瘰疬疮痈

C.川贝母偏于甘润，浙贝母偏于苦泄

D.川贝母、浙贝母均不宜于乌头类药材同用

E.川贝母尤宜用于久咳痨嗽等内伤咳嗽