VOA慢速英语:American History: Nation Grows More Conservative in '20s

1.Under the new law, limits on the number of immigrants from each foreign country depended on the number of Americans who had families in that country.

depend on依赖, 依靠

例句：You can't depend on your parents forever.
      你不能永远依赖你的双亲。

      You may depend on their support.
      你可依靠他们的支持。

2.But the laws were not changed until the election of President Franklin Roosevelt in nineteen thirty-two.

not until直到...才...

例句：He does not leave until midnight.
      直到半夜他才离去。

3.The conflict burst into a major public debate in nineteen twenty-five in a trial over Charles Darwin's idea of evolution.

burst into突然开始(某事), 突然进入(某种状态)

例句：The paper burst into flames.
      那张纸突然着起火来。