若四边形ABCD的相对的两个内角互补,且满足∠A∶∠B∶∠C=2∶3∶4,则∠A=( ),∠B=( ),∠C=( ),∠D=( )
60°; 90° ; 120° ; 90°
—Jane has never been to the Great Wall, _______?
—Yes, she has. She knows it very well. [ ]
A. hasn't she
B. does she
C. has she
根据战伤分类要求,传染病的分类标志是()
A.红色
B.白色
C.黑色
D.黄色
E.蓝色