A
(2017·长沙市模拟试卷二) 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 are 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，and 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 would not mix，enabling the egg to amazingly float in the middle of the glass.
【语篇解读】 本文主要介绍了鸡蛋放入盐水中的实验过程。
【长难句解读】 If you were careful when you added the tap water to the salt water，they would not mix，enabling the egg to amazingly float in the middle of the glass.
[分析] 本句是一个复合句。If引导条件状语从句；when引导时间状语从句；enabling the egg to amazingly float in the middle of the glass是现在分词短语作结果状语。
[译文] 如果你把自来水加到盐水里时比较小心的话，它们就不会混在一起，这样会让鸡蛋在玻璃杯的中间奇迹般地漂浮起来。
1．Which of the following is the CORRECT order?
①Mix in lots of salt.
②Gently lower the egg into the water.
③Carefully pour in plain water until the glass is nearly full.
④Pour water into the glass until it is about half full.
A．④②①③ B．④①③②
C．①④③② D．③④①②
B [考查细节理解。根据第三部分的“Pour water into the glass until it is about half full.”和“Gently lower the egg into the water and watch what happens.”可知，往杯子里倒半杯水是第一个步骤，而轻轻把鸡蛋放进水里，观察结果是最后一个步骤，故选B。]
2．What will happen if you drop an egg into a glass of water with about 6 tablespoons of salt?
A．It will float in the water.
B．It will sink to the bottom.
C．Nothing will happen.
D．The result is not known.
A [考查推理判断。根据第四部分中的“The denser the liquid is，the easier it is for an object to float in it.”和最后一句“If you were careful when you added the tap water to the salt water，they would not mix，enabling the egg to amazingly float in the middle of the glass.”可推知，鸡蛋放入盐水里会浮起来。]
3．Why can the egg float in the water according to the passage?
A．Because ordinary tap water is denser than salt water.
B．Because ordinary tap water is as dense as salt water.
C．Because the denser the liquid is，the easier it is for an object to float in it.
D．Because the more the liquid there is，the easier it is for an object to float in it.
C [考查细节理解。根据最后一部分中的“Salt water is denser than ordinary tap water.The denser the liquid is，the easier it is for an object to float in it.”可知，液体的密度越大，物体越容易漂浮，而鸡蛋能够在盐水中浮起来是因为盐水的密度大，故选C。]
