题目

下列加点字读音全都一样的一组是(    )     A．糜烂  羁縻  麇鹿  靡丽    B．娴静  炫目  晕眩  旋风     C．籼稻  铁锨  翩跹  纤尘    D．淅沥  檄文  嫌隙  畏葸 答案：C(xiān，A靡mǐ，其余读mí  B娴读xián，其余渎xuàn；D声调不同))Scientists say it may be five or six years _____ it is possible to test this medicine on human patients. [     ]A. since B. after C. before D. when