A 55-year-old man, surnamed Huang, can surprisingly lift 50kg of stones with his feet and carry them, along with two dumbbells in his hands for 200 meters in a village in Chengdu, Sichuan province. Huang said that he's walked with stones on his feet every day for years as a way to exercise and he's "worn out" seven pairs of stones.
How many pairs of stones has been worn out by the man?
A. 6
B. 7
C. 8
国内英语资讯:Political advisors study spirit of key CPC meeting
value造句
高中英语作文之苹果7出来了
体坛英语资讯：Colombian defender on Man City radar
国内英语资讯:Top legislature mulls draft laws on cybersecurity, nuclear safety
体坛英语资讯：Uruguay creates commission for joint 2030 World Cup bid with Argentina
世界最高教堂饱受醉鬼尿液摧残
京津冀职称将互认 京冀医疗机构互认
国际英语资讯:Indian police kill 8 militants who fled from prison
为梦想而努力的女孩