Some people think that, in order to improve the quality of education, students should be encouraged to evaluate and criticize their teachers. Others feel that this will result in a loss of respect and discipline in the class room. Discuss both sides and give your opinion.

In ancient time, even in 100 years ago, teachers were treated as sages and regarded as the students' fathers. There is an old Chinese proverb, which is if you are my teacher for even one day, you will be my mentor all my life. It shows the very respect to our teachers, but now changing has occured along with the times, in almost all universities of China, students are asked to evaluate their teachers at the end of any semester in order to improve the quality of education.Someone may say this  respcet should be given to who really deserve it

In many universities, students are asked to

 SDS SLS SDBS各代表什么

实验室中经常用到，但指的是十二烷基磺酸钠还是十二烷基硫酸钠，极易发生混淆。因为前者的英文名为Sodium Dodecyl Sulfonate（此处记为SDS’），后者的为Sodium Dodecyl Sulfate（此处记为SDS）。两者英文词的头一字母均为SDS，但经查化学试剂手册等得知SDS是十二烷基硫酸钠的简称，而不是十二烷基磺酸钠[1]。另外十二烷基硫酸钠也叫月桂基硫酸钠（Sodium Lauryl Sulfate, SLS）是洗洁精的主要成分[2]。
十二烷基磺酸钠与十二烷基硫酸钠均为白色或浅黄色结晶或粉末，溶解于水和乙醇，只是十二烷基硫酸钠常有特殊气味而十二烷基磺酸钠常没有任何气味。在化学结构上尽管两者的烷基部分完全一样，但是取代基不同，前者为磺酸基（—SO3Na），是十二烷与浓硫酸磺化反应后再转成钠盐；后者是硫酸基（—SO4Na），是十二醇与浓硫酸单醋化反应后再转成钠盐，因而分子式与分子量不同，分别为C12H25NaO3，MW272.38和C12H25NaO4，MW288.38。正因它们的结构不同，化学性质及其用途也不同：十二烷基磺酸钠是洗