58._________A. improvements B. factorsC. jobsD. m

The process of scavenging a two－stroke／cycle diesel engine serves to____________.A.improve

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离心泵转速为2900r／min，叶轮外径为200mm，可估算其扬程约为________m。A.42B.58C.116D.168

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【C2】______A．openB．coveredC．secretD．improved

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______ do you think _____ we should do to improve our English？A、／; whatB、what; thatC、wha

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63._________A. increaseB. reduceC. improveD. remo

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_________(62)A.ignore B.improve C.like D.determine

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This text is mainly about______.A．improving cance

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