短语讲解：

1. That year, for the first time, there was more than one candidate for president.

more than 不只是；很；超过；在…次以上
例句：More than 100 people were wounded.
爆炸还造成100多人受伤。

2. Under the electoral system used at that time, the candidate with the most electoral votes became president.

at that time 在那时；当时
例句：They had a problem at that time.
美国商界在当时有个难题。

3. He wrote to his friend James Madison that he was willing to serve under Adams.

be willing to 乐于；甘于
例句：Would you be willing to put that in writing?
你愿意把你的保证写下来么？