有机磷农药中毒的发病机理是( )
A．迷走神经过度兴奋B．交感神经过度兴奋C．抑制胆碱酯酶D．碳氧血红蛋白蓄积E．高铁血红蛋白蓄积
参考答案：C
---What’s wrong with you, Mr. Keller?
--- I’ve had a very bad headache for two days. At first, I ______ I caught a cold, but the medicine ______.
A．thought, hasn’t worked
B．had thought, didn’t work
C．thought, hadn’t worked
D．have thought, hasn’t worked
下列关于元素周期表的叙述，不正确的是[ ]
A．共有7个周期，16个族
B．形成化合物种类最多的元素在第二周期
C．第ⅡA族的右边是第ⅢB族，第ⅢA族的左边是第ⅡB族
D．第ⅠA族包含的元素种类最多
