问题 选择题

下列说法正确的是

A.聚乙烯可使酸性高锰酸钾溶液褪色

B.用新制氢氧化铜悬浊液可以鉴别乙酸、葡萄糖和淀粉三种溶液

C.乙酸与乙醇的酯化反应中是乙酸中羧基氢与乙醇中羟基结合生成水

D.C3H8的二氯代物有3种

答案

答案:B

题目分析:聚乙烯不含碳碳双键,不能被酸性高锰酸钾等氧化剂氧化,因此不能使其褪色,A项错误;氢氧化铜属于难溶性碱,具有弱氧化性、碱性,则新制氢氧化铜悬浊液能溶于乙酸,加热时无砖红色沉淀生成,与葡萄糖混合时不溶解,但共热时产生砖红色沉淀,与淀粉溶液混合时不溶解,但共热时无砖红色沉淀生成,B项正确;乙酸是有机酸,与乙醇发生酯化反应时,乙酸中羧基与乙醇中羟基氢结合生成水,无机含氧酸(如浓硝酸)与乙醇发生酯化反应时,无机含氧酸(如浓硝酸)中羟基氢与乙醇中羟基结合生成水,C项错误;分子式为C3H8的有机物一定是丙烷,无同分异构体,结构简式为CH3CH2CH3,由于同碳上氢等效、位于对称位置的氢等效,则丙烷分子中含有2种氢原子,因此它的二氯代物有4种,分别是1,1—二氯丙烷(CH3CH2CHCl2)、1,2—二氯丙烷(CH3CHClCH2Cl)、1,3—二氯丙烷(CH2ClCH2CH2Cl)、2,2—二氯丙烷(CH3CCl2CH3),D项错误。

阅读理解

How to Become Fit?

Healthy eating habit along with regular exercise is the only way to become fit. If you have the correct number of calories and exercise regularly, you will lose weight, keep fit, and feel great, too.

During your teenage years, it is important to give your body the energy it needs. If you skip (跳过) meals, you won’t get enough calories, and then you will feel tired. By the way, calorie is just another word for energy. About 50% of your calories should come from rice, bread, vegetables and fruit. You also need to drink a lot of water, 6 to 8 glasses a day. Water helps keep your system clean. Drinking enough water will make your skin better and make you healthy.

Exercise is something that can help to make you look good, feel good and be healthy. Experts suggest that teenagers spend at least 30 minutes exercising, five times a week. That is easy to do! You can walk or ride your bike to school, and do sports at school. However, teenagers often give up sports, saying they have no time left after their studies. In fact, doing exercise can help them sleep better at night and increase their ability to focus on their study.

If you follow the suggestions above, you will look and feel much better and become fit.

小题1: What’s the main idea of this passage?

A.How to eat food.

B.How to exercise.

C.How to lose weight.

D.How to keep fit.小题2:The underlined word “calories” means ________ in this passage.

A.营养

B.能量

C.强壮

D.锻炼小题3:Teenagers spend at least _______ minutes exercising a week according to this passage.

A.150

B.50

C.30

D.5小题4: If you ________, you will become fit.

A.exercise regularly

B.drink lots of water

C.eat rice, bread, vegetables and fruit

D.have a healthy eating habit along with regular exercise小题5:Why do teenagers give up sports in school according to this passage?

Because they _________.

A.are lazy

B.feel great

C.are busy with their studies

D.don’t like sports

填空题