晨读晚诵
导语：探索科技世界，服务人类生活。
John Snow
John Snow was born and worked as a doctor in Great Britain. He was famous for using anesthesia¹ which means that he put people to sleep during operations. He also began to experiment using the same drugs to help women when they had babies. That is why he became the doctor for Queen Victoria at the births of her many children.
At the time he lived, cholera was the most frightening disease. There were four outbreaks of cholera in the 1830s and 1840s, which killed many thousands of people.
John Snow believed the cholera came from polluted drinking water. At that time, there was no running water in houses so people had to collect their water from pumps in the street. In addition, they were forced to depend on different water companies to supply them with clean water. So where the water companies collected their water was extremely important. If the drinking water came from the lower part of the River Thames, it could already be polluted. If the drinking water came from the upper² part of the River Thames, it would be clean. Before 1854 John published a paper putting forward the theory that polluted water spread cholera but it did not receive much attention. Then in 1854 he was able to prove that his theory was correct.
译文：
约翰·斯诺
约翰·斯诺是一位出生并就职于英国的医生。他以使用麻醉而闻名，这意味着他让病人在手术中进入睡眠状态。他还试着用同样的药物帮助分娩的产妇。这正是他成为维多利亚女王在分娩她的多个孩子时的医生的原因。
在他所生活的时代，霍乱是最令人恐惧的疾病。在19世纪30年代和40年代共暴发过四次霍乱，夺去了成千上万人的生命。
约翰·斯诺认为霍乱源于被污染的饮用水。那时候房子里没有自来水，因此人们只好从街上的水泵中取水。除此之外，他们不得不依靠不同的供水公司为他们提供干净的水。所以供水公司从哪里取水至关重要。如果饮用水来自泰晤士河的下游，它可能已经被污染了。如果饮用水来自泰晤士河的上游，它可能是干净的。在1854年前，约翰发表过一篇论文，提出了污水传播霍乱的理论，但是未受到太多关注。后来在1854年他得以证明了自己的理论是正确的。
【词海拾贝】
1. anesthesia /ˌænəsˈθiːziə/n. 麻醉
2. upper /ˈʌpə(r)/adj. 上边的，上面的
【理解诱思】
When did John Snow first put forward the theory that polluted water spread cholera?
A. In the 1830s.
B. In the 1840s.
C. In 1854.
D. Before 1854.