To ask, "What is the cheapest possible stuff that you could make a diagnostic system out of, and get useful information, add function?" And what we've chosen is paper.
“世界上什么材料最廉价且适用于制造诊断疾病的仪器， 同时能提供有用的信息， 而且能增添功能？“ 对这一问题，我们的答案是纸张。