Have you ever thought how you'll get drinkable water in the wild？I often advise my students to collect dew（露水）.It's probably the simplest and safest way in a survival situation.
   The only things needed to collect dew are a piece of cloth and a glass.Just wipe（擦） the tiny drops of water on the grass and wring（拧出） the water into the glass.Collect the small drops from grass，rocks and leaves.Do not，of course，collect drops near a highway or in a polluted area.
    You have to get up early and work hard because dew doesn't stay around very long.Some of you might think it's hard to collect enough water using this method.You're wrong.Some of my students have collected more than a quart a day in some of the hottest southwest deserts.On my farm in New Jersey，two students once used this skill to fill a 20-gallon glass with water in less than two hours.
    By the way，although dew is an excellent water source，the same cannot be said for snow.
    Now whenever I tell my students to avoid eating snow，they look at me in surprise as if I was crazy.However，the fact is that it takes a lot of body energy to melt（融化） snow，and in cold weather a person can't afford anything that uses up his/her energy.It's best to melt snow or ice and warm the water before you drink it.You can do so by building a fire or dropping a heated rock into a glass of snow.

请务必将小题的答案写在答题卡的相应位置！
（1）What do people need to use to collect dew？

A piece of cloth and a glass./They need a piece of cloth and a glass.

A piece of cloth and a glass./They need a piece of cloth and a glass.

（2）Why does the writer give two examples of his students collecting dew？

To show the method is useful/effective.

To show the method is useful/effective.

（3）How do the writer's students feel when they are told not to eat snow？

Surprised./They feel surprised./They are surprised.

Surprised./They feel surprised./They are surprised.

（4）How can people melt snow and warm the water？Please list two ways.

By building a fire or dropping a heated rock into a glass of snow.

By building a fire or dropping a heated rock into a glass of snow.

（5）What's the writer's purpose in writing the passage？

To tell people how to get drinkable water in the wild.

To tell people how to get drinkable water in the wild.