VOA慢速英语:Theodore Roosevelt: Energetic

nickname - n. a name that is different from your real name but is what your family and friends call you when they are talking to you or about you

vigorous - adj. done with great force and energy

strenuous - adj. requiring or showing great energy and effort

grief - n. deep sadness caused especially by someone's death

landslide - n. an election in which the winner gets a much greater number of votes than the loser

obligation - n. something that you must do because of a law, rule, promise, etc.

in his own right - n. because of his own efforts, talent, etc., and not because of his connection with someone else

lesson - n. something learned through experience