有正正，正反，反正，反反四种结果，所以P（一正一反）=24=12，故选C．
—What do you often do classes to relax yourself ?
—Listen to music. [ ]
A. over
B. among
C. between
D. through
大黄粉末在日光或紫外光灯下显（）。
A.金黄色荧光
B.橙红色荧光
C.天蓝色荧光
D.乳白色荧光
E.深棕色荧光
