[译] 科学家要为全人类谋利益。
[误] A scientist should benefit all mankinds.

[正] A scientist should benefit all mankind.
[注] mankind (=the human race)作“人类”解时，须用单数。如：Penicillin is a great discovery for the good of mankind. 青霉素是一项有利于人类的重大发现。