His mother kept the family together by establishing a theater company.

VOA: special.2009.05.31

According to this theory, the atoms consist of a positively charged nucleus surrounded by a stream of electrons kept together by attractive forces from the nucleus.

根据这个理论，原子由一个带正电荷的核组成,由于来自核的吸引力,电子流围绕在核的周围。

麻省理工公开课 - 固态化学导论课程节选

According to this theory, the atoms consist of a positively charged nucleus surrounded by a stream of electrons kept together by attractive forces from the nucleus.

根据这个理论，原子由一个带正电荷的核组成,由于来自核的吸引力,电子流围绕在核的周围。

麻省理工公开课 - 固态化学导论课程节选