问题 选择题

下图有关CO2实验,其中只能证明CO2的物理性质的是(  )

A.

B.

C.

D.

答案

A、二氧化碳倾倒后右端下沉,只能证明二氧化碳的密度比空气大,故A正确,

B、盐酸与碳酸钙反应,生产的二氧化碳使右面的蜡烛由下到上依次熄灭,证明了二氧化碳密度比空气大,且不助燃不可燃的化学性质,故B错误,

C、二氧化碳与水反应生成碳酸,使紫色石蕊变红,验证了二氧化碳的化学性质,故C错误,

D、瓶子变瘪,澄清石灰水变浑浊,验证的是二氧化碳的化学性质,故D错误.

故选:A.

写作题

短文填词 根据短文内容和以下提示:1)首字母提示,2)语境提示,3)汉语提示,在每个空格内填入一个适当的英语单词。所填单词要求意义准确,拼写正确。(10分)

A group of swans (天鹅)flew down to a beach where a crow(乌鸦)was jumping around. The crow watched t     with disdain(鄙视).

“You have no flying skills at all!” he said to the swans. “ All you can do is to move your wings. Can you turn over in the air? No, that’s      (超出) you. Let’s have a flying competition. I’ll show you what real flying is!”

One of the swans, a strong young male, took up the challenge. The crow flew up and began to show his skills. He flew in circles,        (表演) other flying tricks, and then came down and looked at the swan        (自豪地).

Now it was the swan’s       . He flew up, and began flying over the sea. The crow flew after him, making all kinds of comments(评价)about his flying. They flew on and on till they couldn’t see the land and there was        but water on all sides. The crow was making fewer and fewer comments. He was now so tired that he found it hard to stay in the air, and had to struggle to keep himself from falling       the water.

The swan pretended(假装)not to notice, and said, “Why do you  k     touching the water, brother? Is that another trick?”

“No, ” said the crow. He knew he had       the competition. “I’m in trouble because of my pride! I   you don’t help me , I’ll lose my life……”

The swan took pity on him, and took him on his shoulders and flew back to the beach.

问答题