was able to/could1

【问】 (1)Gauss was able to show by a theoretical analysis that the field arose within the solidearth...(北大《英语》(三),P.101)[原译]高斯通过理论分析能够证明场是在地球实体内产生的……(教参)(2) After years of difficulty,Whittle was,however,able to build his firs ......(本文共 2085 字)     [阅读本文]>>



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