病因判断标准中下列哪项是必需的()。
A.关联的时间顺序:先“因”后“果”
B.关联的强度
C.关联的可重复性
D.关联的合理性
E.剂量-反应关系
参考答案:A
图为“沿某纬度所作的海陆剖面示意图”,甲点典型植被类型为 ( )
A.热带雨林
B.热带草原
C.常绿硬叶林
D.落叶阔叶林
—Were you caught in the rain yesterday?
—Good luck. No sooner home than it poured down.
A.I had reached
B.had I reached
C.did I reach
D.I have reached