在四边形ABCD中,如果∠B+∠C=180°,那么 [ ]
A.AB∥CD
B.AD∥BC
C.AB与CD相交
D.AB与DC垂直
答案:A
Green products are becoming more and more popular because they are environmentally _________.
A.friendly
B.various
C.common
D.changeable
阿片受体拮抗药为()
A.苯佐那酯
B.吗啡
C.喷他佐辛
D.喷托维林
E.纳洛酮