对硫磷农药体内转化、经氧化作用可以使产物（）
A.毒性增强
B.毒性降低
C.毒性不变
D.物理性状改变
E.作用器官改变
参考答案：A
请写出当地常见的5种乙类传染病和5种丙类传染病
----Li Feng won the first prize in the national English competition.
----Oh, really? I’m glad that his hard work at last _____.
A．worked out
B．got back
C．paid off
D．turned out
