二氢叶酸合成酶的竞争性抑制剂是
A．敌百虫B．丙二酸C．磺胺类药物D．琥珀酸
参考答案：C
My cousin, little Tom, is __________ a fool. He did very well in all his subjects.
A．something as
B．something but
C．anything but
D．nothing but
划分液压油牌号的粘度采用的温度是（）。
A、100℃
B、50℃
C、20℃
D、40℃
