题目

Two American scientists told the people in industrial nations that they would be much healthier if they ate more of the same kind of foods eaten by humans living more than 10,000 years ago． The scientists say that the human body has changed very little since human first appeared on earth, but the way we live has changed greatly．Our body has not been able to deal with these changes in life style and this has led to new kinds of sicknesses．These new sicknesses were not known in ancient times．So they are called “diseases of civilization （文明）”．Many cancers and diseases of th只有一把30cm的刻度尺测量一层楼教学楼的高度，请说出实验的方法及怎样得出一层教学楼的高度。