苯巴比妥的乙醇溶液澄清度检查物质是（）.
A．苯丙二酰脲
B．酸性杂质
C．2-苯基丁酰胺
D．对氨基酚
E．苯基丁酰脲
参考答案：B
角平分线一定垂直于底边[ ]
—Tom，you are caught late again.—Oh，（）.
A. not at all
B. just my luck
C. never mind
D. that's all right
