工业革命以来,世界人口增长速度明显加快的根本原因是[ ]
A.人口出生率低
B.人口死亡率高
C.人口自然增长率低
D.社会生产力水平提高
答案:D
Was it in the park _____ he often did morning exercises _____ he met his beloved wife? [ ]
A. that; that
B. where; where
C. where; that
D. that; where
根据动物实验和流行病学研究结果,已确认氯甲甲醚、石棉和砷等为人类致癌物。欲早期发现这些毒物所致职业性肿瘤,定期健康检查时应常规检测的项目是
A.胸部X线拍片或痰细胞学检查B.膀胱镜检或小便沉渣中脱落细胞检查C.肝B超或肝功能试验D.血液学检查E.血、尿常规检查