29. The Chinese, who ……………….. paper more than 2,000 years ago, first painted on it. A. inventing B. invented C. had invented D. were inventing 30. People live in all kinds of climates, ranging ……………….. the tropics to the Arctic. A. from B. at C. in D. through 31. Running helps control weight ………………….. runners burn up more than 100 calories per mile. A. though B. however C. because D. whatever 32. Many coaches and sports officials begin their careers as ………………… A. athletics B. athletes C. athletic D. athlete 33. - "Could I try on this dress ?" - " Yes, of course. ……………………. " A. It's cheap enough B. The changing room's over there C. It's in good condition D. The cashier's over there 34. Scientists who study the relationships between living things ………………….. ecologists. A. called B. calling C. call D. are called