An Interesting Experiment

    Put an ice cube(冰块) from your fridge into a glass of water.{#blank#}1{#/blank#} Thus, you can take out that piece of ice with the help of the string. But you must not touch the ice with your fingers.

    You may ask your friends to try to do that when you are having dinner together.{#blank#}2{#/blank#} You must use salt when you carry out this experiment.

    {#blank#}3{#/blank#} Then put some salt on the ice. Salt makes ice melt(融化). The ice round the string will begin to melt.{#blank#}4{#/blank#} The cold ice cube will make the salt water freeze again.

    After a minute or two you may raise the piece of string and with it you will raise your piece of ice!

    This experiment can be very useful to you. If, for example, there is ice near the door of your house, you must use very much salt to melt all the ice.{#blank#}5{#/blank#}

A. If you don't put enough salt, the water will freeze again.

B. The string must be at least 10 centimeters long.

C. First you put the string across the piece of ice.

D. We can learn a lot from this physical experiment.

E. But when it melts, it will lose heat.

F. You should have a piece of string 10 centimeters long.

G. There is a salt bottle on the table.

森林遭到严重砍伐后，我们可能面临下列哪些问题？（　　）