VOA慢速英语:A Rolling History of Americans on the Move

例句：They don't want to stretch the meeting out.
      他们不想把会议延长。

2.waterway n.航路,水路,运河

例句：Canals and rivers form the inland waterways of a country.
      运河和河流构成一个国家的内陆航道。

3.throughout ad.在所有各处,彻头彻尾,自始至终

例句：Fog will persist throughout the night.
      雾将整夜不散。

4.strengthen v.加强,变坚固

例句：His opposition served only to strengthen our resolve.
      他一反对反而增强了我们的决心。

5.suburb n.市郊,郊区,边缘

例句：The located in a suburb close to London.
      他们在靠近伦敦的郊区定居。