VOA慢速英语:英美队伍共享千万美元XPRIZE大奖

philanthropist - n. a wealthy person who gives money and time to help make life better for other people

source - n. a person, book, etc., that gives information

tablet - n. a flat, rectangular computing device that is used for connecting to the Internet, watching videos, reading books, etc.

transformational - adj. relating to a complete or major change in someone's or something's appearance, form, etc.