单选题 When he lived in Tibet in 1950s, radio was the only means he had to keep of current events in the country.

【正确答案】 B

【答案解析】track行踪，keep track of系固定搭配，意为“听清，看清，掌握……的线索”句意：20世纪50年代他住在西藏时，收音机是他了解时事动态的惟一工具。A. response回答，反应；C record记录；D．trace足迹，踪迹。