39．To show that Frost can become a great poet due to his unhappy childhood.
归纳表达题。由第三段第二、三句“The best thing, he said, was to have an unhappy childhood. If this is true, Robert Frost's childhood was unhappy enough to make him a very good writer.”可知本文提到海明威是为了阐明正是有一个不幸的童年造就了罗伯特·弗罗斯特，使他成为一位伟大的诗人。
40．Dartmouth College
代词指代题。由画线词前两句“After high school, Robert's grandfather offered to pay his costs at Dartmouth College. But Robert left the school after a few months.”可知it应该指的是前面提到的Dartmouth College。
