问题 选择题

在2CuS+4H2SO4(浓)=2CuSO4+2SO2↑+2S+4H2O反应中,被氧化的元素是( )

A.Cu

B.S

C.O

D.无法确定

答案

答案:B

考查氧化还原反应的有关判断。在氧化还原反应中被氧化的元素,其化合价是升高的。被还原的元素化合价是降低的。根据反应式可知浓硫酸中硫的化合价从+6价降低到+4价。硫化铜中S的化合价从-2价升高到0价。所以浓硫酸是氧化剂,SO2是还原产物。硫化铜是还原剂,单质硫是氧化产物。答案选B。

完形填空

Directions: Read the following passage. Answer the questions according to the information given in the passage and the required words limit.(6 points)

Write your answers on your answer sheet.

As we rush through our busy days accomplishing our tasks-work,kids,shopping,cleaning, eating and so on,we often complain that we don’t feel good.There is a simple,quick,and effective way that you can feel better throughout the day and also be more attractive.

All you have to do is smile more.

Smiling changes your attitude,whether you realize it or not.If you have any doubts,next time you feel down,start smiling and thinking positive thoughts and see what happens.You can’t help but have a better attitude when you smile.

Smiling also raises your confidence.

Smiling affects your emotions because of a brain-body connection.It triggers scientifically measurable activity in the left,frontal cortex-the area of the brain where happiness is registered.

Your face has 44 muscles between the skin,cartilage(软骨),blood and bone that you contort(扭曲), flex, and move.This lets you make over 5000 different types of expressions.That’s a lot of expressions! And each will have a different effect on your feelings and those looking at you.

Now that you know how good smiling is for you,make a conscious effort to use this smile  exercise a minimum of six times throughout your day.When you smile,remember to breathe in  through your nose and think positive thoughts.This I guarantee will have a positive influence on  your day and in your life.So smile!  

76.How can you feel good and be more attractive according to this passage?(within 2 words.)

_______________________________________________________________________________77.Why can we make more than 5,000 different types of expressions?(within 19 words.)

_______________________________________________________________________________78.What are the benefits of smiling?(within 12 words.)

单项选择题