目前人类已知的宇宙( )
A:半径约为200亿光年
B:是时间和空间的统一体
C:星云和恒星是主要天体
D:由星系和总星系组成
It was this exploring around problems and his ____(充满活力的) spirit that led to his most famous invention—the telephone in 1876.
①种植园主 ②教士 ③新贵族 ④资产阶级