VOA慢速英语:China’s President Supports Free Trade at World Economic Meeting

tariff - n. a tax on goods coming into or leaving a country

pursue - v. to move ahead with a policy or course of action

lock - v. to become fixed in one position

challenge - n. a difficult task or problem

automation - n. to run or operate something such as a factory by using machines, computers or robots instead of people to do the work

volatility - adv. likely to change in a very sudden or extreme way

vacuum - n. an empty space