If the atom is fixed mass, the electron is tiny, It must be the positives have all the mass.

如果是原子质量一定，电子很小，带正电荷的部分几乎占据了全部质量。

麻省理工公开课 - 固态化学导论课程节选

In the 1830s 600,000 immigrants came to the United States, almost entirely from Western Europe; in the 1840s alone 1.5 million; and in the 1850s,almost 3 million more.

十九世纪三十年代,约有六十万人移居美国,几乎全部来自西欧,仅在四十年代,就有一百五十万移民,而在五十年代,又多了三百万

耶鲁公开课 - 美国内战与重建课程节选