was able to/could¹
人文科学

        【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] >>