1题 21473856
2题
1John Snow finally proved his idea because he found an outbreak that was clearly related to cholera,collected information and was able to tie cases outside the area to the polluted water.
2No.The map helped John Snow organize his ideas.He was able to identify those households that had many deaths and check their water-drinking habits.He identified those houses that had no deaths and surveyed their drinking habits.The evidence clearly pointed to the polluted water being the cause.
3Four diseases,which are similar today,are SARS,AIDS,TB (肺结核) and bird-flu,because they are both very serious,have an unknown cause and need public health care to solve them.