现有氧气、二氧化碳、氮气、一氧化碳,用化学式填写下列空格: 使澄清石灰水变混浊的

题型:填空题

问题:

现有氧气、二氧化碳、氮气、一氧化碳,用化学式填写下列空格:

使澄清石灰水变混浊的是______,空气中含量最多的气体是______,使带火星的木条复燃的是______,有毒的是______.

考点:化学式的写法和意义
题型:填空题

阅读理解。

     One day a farmer's donkey fell down into a well. The animal cried piteously for hours as the farmer tried

to figure out what to do. Finally he decided to give up because the animal was old, and the well needed to

be covered up and it just wasn't worth it to retrieve the donkey. So he decided to bury the donkey.

     He invited all his neighbors to come over and help him. They all grabbed a shovel (铲) and began to shovel

dirt into the well. At first, the donkey realized what was happening and cried horribly then slowly he became

quiet.

     A few shovel loads later, the farmer finally looked down the well, and was surprised at what he saw: With

every shovel of dirt that hit his back, the donkey was doing something amazing. He would shake it off and take

a step up.

     As the farmer's neighbors continued to shovel dirt on top of the animal, he would shake it off and take a

step up. Pretty soon, everyone was amazed as the donkey stepped up over the edge of the well and happily

got out!   

     Life is going to shovel dirt on you, all kinds of dirt. Each of our troubles is a stepping stone. We can get

out of the deepest wells by not stopping, never giving up, shaking it off, and taking a step up!

1. The farmer _______ and decided to give up getting the donkey out at last.

A. couldn't get the donkey out

B. thought the donkey was old

C. knew the well was useless

D. All of the three

2. The donkey cried again because it _______.

A. didn't like the dirt.

B. knew it was being killed

C. was angry

D. felt uncomfortable

3. The donkey _______ so it became quiet.

A. found a way to save itself

B. was killed by the farmer

C. felt hopeless

D. was too tired to cry

4. The donkey saved itself by _______.

A. making the trouble a stepping stone.

B. asking the neighbors for help.

C. thinking of something worse.

D. learning to forget.

5. We can learn some simple rules from the story, they are: _______.

A. Free your mind from worries.

B. Free your heart from hated. (憎恨)

C. Give more and expect less.

D. all the above.

题型:填空题

下列所示约图象与实验相符合的是(  )

A.饱和Ca(OH)2溶液升温

B.镁在空气中燃烧

C.向含少量氢氧化钠的碳酸钠溶液中逐渐加入稀盐酸过量

D.等质量的镁片,锌片分别和足量的稀硫酸反应

题型:填空题

天然气甘醇脱水装置中,重沸器的火管形状一般为()

A.L形

B.M形

C.N形

D.U形

题型:填空题

挥发油的酸值是指

A.水解1g挥发油中所含的酯基需要的氢氧化钾的毫克数

B.中和1g挥发油中的酸性成分所消耗氢氧化钾的毫克数

C.皂化且尽挥发油所消耗氢氧化钾的毫克数

D.皂化值与酯值之和

E.挥发油中酚类成分的含量指标

题型:填空题

下列哪一项不是掌上电脑的主要特色()

A.移动办公

B.商务助理

C.网络应用

D.PC伴侣

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