第二部分阅读理解(共两节，满分40分)

　　第一节 (共15小题;每小题2分，满分30分)

　　阅读下面短文，从每题所给的A、B、C、D四个选项中，选出最佳答案，并在答题卡上将该项涂黑。

　　A

　　An egg sinks to the bottom if you drop it into a glass of ordinary drinking water

　　but what happens if you add salt? The results arc very interesting and can teach you some fun fACTs about density(密度) .

　　What you'll need :

　　*One egg *Water *Salt *A tall drinking glass

　　Instructions :

　　Pour water into the glass until it is about half full.

　　Mix in lots of salt (about 6 tablespoons) .

　　Carefully pour in plain water until the glass-is nearly full (be careful not to mix the salt water with the plain water) .

　　Gently lower the egg into the water and watch what happens.

　　What's happening?

　　Salt water is denser than ordinary tap water. The denser the liquid is, the easier it is for an object to float in it. When you lower the egg into the liquid it drops through the normal tap water until it reaches the salt water, at this point the water is dense enough for the egg to float. If you were careful when you added the tap water to the salt water, they will not have mixed, enabling the egg to amazingly float in the middle of the glass.