问题 选择题

下列物质放入或通入水中,能使pH增大的是(  )

A.NaCl

B.白醋

C.干冰

D.生石灰

答案

A、氯化钠是中性的物质其pH值为7,和水的相等,故A错

B、白醋是酸性的物质,其pH小于7,加入水中后会使pH降低,故B错

C、干冰是二氧化碳的固态,能够溶于水,生成碳酸,pH小于7,从而使pH降低,故C错

D、生石灰可以和水反应生成氢氧化钙,氢氧化钙溶于水后使溶液pH大于7,使溶液的pH增大,故D对

故选D

阅读理解

"Make-A-Wish” is one of the world's most well-known charities(慈善机构) . It makes wishes come true for childrenwho have serious illnesses. It gives them hope and joy and helps them forget about their health problems and have fun.

It all started in 1980 in Phoenix, Arizona. Christopher was a 7-year-old boy who was very sick. He always dreamed ofbecoming a police officer. Tommy Austin and Ron Cox, two police officers, made his wish come true. They gaveChristopher a tour of the city in a police helicopter(直升飞机)and made a real police uniform(制服) for him.

There are four kinds of wishes children usually have:

I wish to go. Children usually want to travel or go to a concert, a game or a park.

I wish to meet. Children sometimes want to meet their favourite actors, singers or players.

I wish to be. Some children wish to become actors, singers or police officers.

I wish to have. They often want to have a computer, a game, a bike or many other things.

Let’shope more wishes Mill come true in the future. People who work in the charity always try for the best. Almost25 ,000 Volunteers (志愿者) help, work or give money. Will you be one of them?

小题1:"Make-A-Wish" is a charity to help _______.

A.sick children

B.serious officers

C.famous actors

D.popular singers小题2:What did the two police officers do for Christopher?

A.They gave him a computer.

B.They gave him a tour of the city.

C.They look him to a concert.

D.They took him to the hospital.小题3:Which kind of wishes does Christopher have?

A.I wish to go.

B.I wish to meet.

C.I wish to be.

D.I wish to have.小题4:The purpose of the last paragraph is to _______.

A.explain what " Make-A-Wish" is

B.encourage more people to join the charity

C.tell us how Christopher's wish came true

D.introduce different kinds of children's wishes小题5:Which of the following is TRUE according to the passage?

A.Sick children just wish to get well.

B.Christopher and Tommy are two officers.

C.A few people are working for "Make-A-Wish".

D."Make-A-Wish" has a history of over 30 years.

单项选择题