若等腰三角形的底角为54°,则顶角为
A.108°
B.72°
C.54°
D.36°
答案:B
∵等腰三角形底角为54°
∴顶角=180°-(54°×2)=72°
故选B.
下列炮制方法对含生物碱类药物没有影响的是
A.醋制
B.热制
C.水制
D.酒制
E.姜汁制
34. The designs of the new tools should be ________ carefully, so that we can pick out the one that suits our work.
A.experimented
B.examined
C.exercised
D.tried