问题 选择题

下列有关化学基本概念的判断依据正确的是(  )

A.共价化合物:是否含有共价键

B.氧化还原反应:元素化合价是否变化

C.强弱电解质:溶液的导电能力大小

D.离子晶体:液态时能否导电

答案

A、含有共价键的化合物不一定为共价化合物离子化合物中也可能含有共价键,如NaOH,故A错误;

B、氧化还原反应的特征是有化合价的变化,可以根据元素化合价是否变化来确定是否是氧化还原反应,故B正确;

C、溶液的导电能力和电解质的强弱无关,根据电解质在水溶液中是否完全电离将电解质分为强电解质和弱电解质,故C错误;

D、离子晶体中含有离子键,液态时能否导电的不一定是离子晶体,如金属单质,故D错误.

故选B.

阅读理解

阅读理解。

     As a parent you might never guess all the ways a good imagination benefits your child. It helps a

preschooler:

     Develop social skills

     As children play pretend, they explore relationships between family members, friends and co-workers

and learn more about how people interact. Playing doctor, they imagine how physicians care for their

patients. Playing house, they learn more about how parents feel about their children. Imaginative play

helps develop sympathy for others. If children can imagine how it feels to be left out of a game or to lose

a pet, they are better able to help those in need. They become more willing to play fair, to share, and to

cooperate.

     Build self-confidence

     Young children have very little control over their lives. Imagining oneself as a builder of skyscrapers

or a superhero defending the planet is empowering to a child. It helps them develop confidence in their

abilities and their potential.

     Boost intellectual growth

     Using the imagination is the beginning of abstract thought. Children who can see a king's castle in a

mound of sand or a delicious dinner in a mud pie are learning to think symbolically. This skill is important

in school where a child will have to learn that numerals symbolize groups of objects, letters symbolize

sounds, and so on.

     Practice language skills

     Kids who play pretend with their friends do a lot of talking. This helps boost their vocabulary, improve sentence structure and enhance communication skills.

     Work out fears

     Playing pretend can help children work out their fears and worries. When children role-play about the

big, bad monster under the bed, they gain a sense of control over him and he doesn't seem quite so big

or so bad. Imaginative play also helps kids let out confusing feelings they might have, such as anger

toward a parent or rivalry(竞争) with a new sibling(兄弟姐妹).

     To encourage your youngster's imagination, read to him every day. Books offer children the

opportunity to visit other worlds and create new ones of their own.

     For generations children have enjoyed reading the story of Peter Pan because Peter takes them on

fascinating adventures. Reader's Digest Young Families offers a beautiful vintage Disney edition of Peter

Pan, which is an iParenting Media Award winner. Click here to find out how you can get this classic

story along with 2 free books - Bambi and Pinocchio.

1. Where can you probably find the article?    

A. Newspaper

B. Magazine

C. Internet

D. Book

2. What's the meaning of the underlined word?

A. improve

B. limit    

C. pull    

D. praise

3. What's the purpose of writing the article?

A. Tell the readers 5 benefits of encouraging the child's imagination.

B. Advise the parents to encourage the child's imagination.

C. Introduce some Disney stories to the readers.

D. Persuade the parents to buy books for their children.

单项选择题