The challenge is if certain types of people are doing something, it's difficult for other people to break into it, said Po-Shen Loh, the head coach of last year's winning U.S.Math Olympiad team.
出自-2017年6月閱讀原文
In 2018, farmers will plant the varieties with the most promise in the Ebro Delta and Europe's other two main rice-growing regions—along the Po in Italy, and France's Rhone.