VOA慢速英语:Hoover Dam: Taming the Colorado River and Providing Electricity to Millions

例句：He bypassed his colleagues on the board and went ahead with the deal.
      他未征求董事会中同事的意见就做了这笔交易。

2.demonstrate vt.说明, 演示

例句：Recent events demonstrate the need of change in policy.
      最近的事态表明政策需要改变。

      This demonstrates that all power belongs to the people.
      这说明一切权力属于人民。

3.flee vi.逃走, 逃掉

例句：Samuel has fled.
      塞缪尔已经逃跑了。

4.strengthen vt.vi.加强, 巩固

例句：The wind strengthened during the night.
      夜里风刮得更大了。

      They strengthened the city walls.
      他们加固了城墙。

5.dedicate vt.奉献; 贡献; 把…奉献给

例句：He dedicated his life.
      他奉献出自己的生命。