CNN news 2010-08-25 加文本

1.And American officials say the unmanned vehicles help cut down risk for troops because no one actually has to be on board piloting it.

cut down减少, 降低

例句：We were for cutting down the cost of production.
      我们赞成降低成本。

      You must cut down on sugar to lose weight.
      你必须少吃糖以减轻体重。

2.Pakistan's long-standing electricity shortage is suddenly so much worse because power plants have been shut down or damaged as well.

shut down完全关闭，倒闭，停止运转

例句：The shop has shut down because of lack of trade.
      那商店因生意萧条而停业。

      She shut the lid down.
      她扣上了盖儿。

3.What the floods have done is to virtually wipe out an infrastructure, agricultural infrastructure that it depended upon for its wheat exports.

wipe out彻底摧毁, 消灭

例句：The plague once could wipe out a village.
      鼠疫曾一度可以夺走整个村庄村民的生命。

      We are always ready to wipe out any enemy who dares to attack.
      我们时刻准备着消灭一切胆敢来犯之敌。