问题 多选题

可以用来鉴别烧碱和纯碱的是(  )

A.醋酸

B.紫色石蕊

C.无色酚酞

D.氯化钡溶液

答案

A、醋酸和烧碱反应生成醋酸钠和水,无明显现象,而醋酸和纯碱反应生成二氧化碳,反应中会看到气泡现象,故A正确;

 B、烧碱和纯碱都显碱性,都能使紫色石蕊试液变蓝,无法用石蕊试液鉴别,故B错误;.

 C、烧碱和纯碱都显碱性,都能使无色酚酞试液变红,无法用无色酚酞鉴别,故C错误;

 D、纯碱可以和氯化钡反应生成碳酸钡沉淀,而烧碱和氯化钡不反应,无现象,故D正确.

故选:A、D.

阅读理解

A leading biologist has found the angels and fairies that sit at top of Christmas trees did not get there under their own power.

Prof Roger Wotton, from University College London, found that flight would be impossible for angels with arms and bird-like feathered wings. 

"Angels cannot take off and cannot use powered flight,” said Prof Wotton. “They would need to be exposed to very high wind velocities at take off - such high winds that they would be blown away."

Some the world’s most famous religious paintings and architecture make most Americans believe in angels.

The study found that 68 per cent of the 36,000 adults thought that angels and demons (魔鬼) were at work in the world.

According to the latest study, angels lack the powerful muscles which allow birds to beat their wings.

Prof Wotton’s paper explores why there are so many stories about angels. “Angels are very powerful religious icons for people with faith. Their similarity to humans adds to their power. At the same time, they have wings on them because they are more than human. They take messages to heaven and therefore have to fly.” said the academic.

小题1:What did the leading biologist find?

A.The angels and fairies are very powerful.

B.It’s impossible for angels and fairies to fly.

C.The flight would be possible for angels with arms and bird-like feathered wings.

D.The angels and fairies can sit on the tree under their own power.小题2:What’s the Chinese meaning of the word “architecture” ?

A.油画

B.建筑

C.鸟巢

D.天堂小题3:According to the article, how many adults thought that there were real angels and demons?

A.68.

B.36,000

C.24,480

D.3,600小题4: Which of the following is True?

A.Angels can’t fly because they lack the powerful muscles which allow birds to beat their wings.

B.Most Americans don’t believe in angels.

C.Angels can take off and can use powered flight.

D.Angels are not the same to the humans.小题5:Why do many people believe angels can fly?

A.Angels are real human beings.

B.Angels with wings can take messages to heaven and therefore have to fly.

C.Angels are very similar to the humans.

D.Angels are powerful.

单项选择题