问题 选择题

下列安全事故处理错误的是(  )

A.使用水银温度计测量烧杯中水浴温度时,不慎打破水银球,用滴管将水银吸出放入水封的小瓶中,残破的温度计插入装有硫粉的广口瓶中

B.误食重金属盐,立即喝生牛奶或蛋清

C.不慎将浓H2SO4沾在皮肤上,立即用NaOH溶液冲洗

D.金属钠着火,立刻用砂子覆灭

答案

答案:C

水银不溶于水,密度大于水,且极易和;硫反应生成硫化银,A正确。重金属盐能使蛋白质变性,牛奶或蛋清均是蛋白质,B正确。氢氧化钠和硫酸反应会放热,加速皮肤的灼烧,C不正确,正确的做法是用干布迅速擦去,然后再用大量水冲洗,最后涂上硼酸溶液。钠极易和水反应,所以钠着火要用沙子扑灭,D正确。答案选C。

阅读理解

Once there was a huge apple tree. A little boy loved to come and play around it every day. He loved the tree and the tree loved to play with him.

Time went by — the little boy had grown up and he no longer played around the tree every day. One day, the boy came back to the tree and he looked sad. “Come and play with me,” the tree asked the boy. “I’m no longer a kid. I wouldn’t play around the tree any more.” the boy replied. “I want toys. I need money to buy them.” “Sorry, I don’t have money. But you can pick all my apples and sell them. So, you will have money.” The boy picked all the apples on the tree and left happily. The boy never came back after he picked the apples.

One day, the boy returned and the tree was so excited, “Come and play with me,” the tree said. “I don’t have time to play. I have to work for my family. We need a house for shelter. Can you help?” “Sorry, I don’t have a house. But you can cut off my branches to build your house.” So the boy cut all the branches off the tree and left happily. The tree was glad to see him happy but the boy never came back since then. The tree was again lonely and sad.

One hot summer day, the boy returned and the tree was pleased. “Come and play with me!” the tree said. “I am sad and getting old. I want to go sailing to relax myself. Can you give me a boat?” “Use my trunk to build your boat. You can sail far away and be happy.” So the boy cut the tree trunk to make a boat. He went sailing and never showed up for a long time.

Finally, the boy returned after he left for so many years. “Sorry, my boy. But I don’t have anything for you any more. The only thing left is my dying root,” the tree said with tears ①

“Good! Old tree root is the best place to lean on and rest. Come and sit down with me and rest.” The boy sat down and the tree was glad and smiled with tears ② ……

小题1:Why did the boy pick all the apples on the tree? Because __________.

A.he wanted to eat them

B.he needed money to buy toys

C.he liked the tree without apples

D.he wanted to share them with friends.小题2:When did the boy come back to the apple tree? He came back _________.

A.whenever he was happy

B.if he missed the apple tree

C.when he was in times of difficulty

D.as soon as he was free小题3:What did the boy want at last? He wanted ___________.

A.to have a house to live in

B.nothing except a place to rest

C.the root of the apple tree

D.anything that the apple tree had小题4:What can we learn from the story? We should _________.

A.plant more apple trees

B.learn from the boy

C.always stay at home

D.be thankful to our parents小题5:According to the passage, which of the following is NOT true?

A.The phrase “with tears ①” means that the apple tree was sad because the boy asked for too much.

B.The phrase “with tears ②” means that the apple tree was still happy because she could help the boy for the last time.

C.Each time the boy asked the apple tree for help, the tree tried her best to satisfy him.

D.After reading the passage, we can easily think of the old Chinese saying “Parents’ love is universal!”

单项选择题