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agricultures 。 agriculture C. research’s。 the ( ) 30. In western countries, ________ are thrown away each day. A. mountains of rubbish B. mountains of rubbishes C. a lot of rubbish D. a lot of rubbishes ( ) 31. He is trying to explain how ________ began on the earth. A. life B. lives C. the life D. a life ( ) 32. Look, the police ________ ing. A. is B. were C. are D. was ( ) 33. Writing positions in English is not ________. A. easy job B. an easy work C. an easy job D. the easy work ( ) 34. China was the earliest ________ center for ________. A. research’s。 the C. the。 / ( ) 13. Can you see _________ sun in the daytime? A. a B. the C. an D. / ( ) 14. The singer usually sings while playing ________ guitar. A. a B. an C. the D. / ( ) 15. I’ve got information for