亚洲三个人类文明的发祥地是____________、___________、________________。
黄河-长江中下游地区;印度河流域;美索不达米亚平原
When Madam Cuirie did the science experiement again, she was more careful where she _____ a mistake.
A.made
B.has made
C.was making
D.had made
机械密封注封油能防止输送介质泄漏和负压下空气或冲洗水进入填料函。