用反证法证明命题“一个三角形中不能有两个角是直角”,应先假设这个三角形中 [ ]
A.有两个角是直角
B.有两个角是钝角
C.有两个角是锐角
D.一个角是钝角,一个角是直角
答案:A
____ a more comfortable life, the poor couple worked hard and took on more part-time jobs.
A.Aiming at
B.Adding to
C.Relating to
D.Taking advantage of
阿托品的禁忌证是
A.青光眼B.肠绞痛C.有机磷农药中毒D.流涎E.抑制腺体分泌