具有抗疟活性的是
A.乌头碱
B.马桑毒素
C.雷公藤内酯
D.紫杉醇
E.青蒿素
参考答案:E
解析:青蒿素是青蒿(黄花蒿)中分离到的具过氧结构的倍半萜内酯,有很好的抗恶性疟疾活性。
函数f(x)=(a-1)ax为R上增函数则实数a的范围为______.
At the party, John made up a joke, people burst out laughing.
A.on which
B.by which
C.at which
D.from which