Eleven dollars per part at 12.5 million cars and trucks came to a total cost of $137 million to improve the safety.

给1250万辆轿车和卡车配上11美元的隔板,提高安全性，共需花费一亿三千七百万美元。

耶鲁公开课 - 公正课程节选

Then, they did preliminary studies of safety and effectiveness in people.

接着,研究人员对疫苗在人体中的,安全性和有效性进行初步研究

耶鲁公开课 - 生物医学工程探索课程节选