考题回忆：总论点Amalgam should be prohibited in dental repairs
1.Amalgam is harm to people’s health, which will invade in nervous system and bring series of illness.
2. Mercury in Amalgam will drain into waterways, polluting rivers and lakes.
3. There are substitutes of Amalgam, such as gold and ceramic.
1.The recent study shows that with a small amount of mercury, human body will not be harmed.
2.Most of dentists have a solution to prevent mercury from flowing into sewer systems to pollute environment.
3. Mercury has lots of advantages.
参考范文：The reading material believes that Amalgam should be prohibited in dental repairs. However, the professor in the listening refutes the idea of the reading and provides reasons from three aspects.
Firstly, the reading argues that Amalgam is harm to people’s health, which will invade in nervous system and bring series of illness. By contrast, the professor hold the view that the recent study shows that with a small amount of mercury, human body will not be harmed. Furthermore, Those people who are affected significantly as reading mentioned are allergic.
Secondly, the reading material gives another threat of Amalgam. Mercury in Amalgam will drain into waterways, polluting rivers and lakes. However, the lecture clearly indicates that most of dentists have a separator in their offices, a kind of filter which can collect solid materials and prevent water with mercury from flowing into sewer systems to pollute body of water.
Finally, the reading material insist that There are substitutes of Amalgam, such as gold and ceramic. On the contrary, the professor refute with some details. He says that mercury has lots of advantages. It can last longer than other materials in human's wet mouth. Also, gold is expensive. It can increase cost of dental by 12 billion dollars every year.
考题回忆：Which one is the most important factor to help you work productively:
A. Having an environment free of noise and distractions;
B. Knowing that you will receive a reward;
C. Doing something you are interested in.