do one's best to do =try one's best to do =尽某人的最大努力做某事. one's是物主代词,根据主语的变化而变化 如果主语I 就用my 如果是you 就用your. They did their best to help the people in trouble in trouble:在困难中. 他们尽了最大的努力帮助在困难中的人们
do one's best to do 尽最大努力做某事(一般多说try one's best to do ) one's 是形容词性物主代词 to do 是动词不定式做目的状语,是尽最大努力去完成那个事(达成的那个目的) in trouble 处在困境中的、有麻烦的 此处是介词短语作定语修饰the people