为了研究酶的有关特性,取两支洁净的试管并编号A、B,各注入2mL体积分数为3%的

题型:读图填空题

问题:

为了研究酶的有关特性,取两支洁净的试管并编号A、B,各注入2mL体积分数为3%的H2O2溶液;再向A管滴入2滴3.5%的FeCl3溶液,向B管滴入2滴质量分数为20%的肝脏研磨液;堵住管口,轻轻振荡;用点燃但无火焰的卫生香检查;观察并记录结果。

(1)本实验的主要目的是探索_______________。

(2)如果两支试管的现象均不明显,从实验材料分析,原因可能是_________。

(3)过氧化氢酶也能催化H2O2的分解,产生的[O]能使溶于水的无色焦性没食子酸氧化生成橙红色沉淀。为了鉴定马铃薯块茎是否含有过氧化氢酶,设计了如下实验:

①.3号试管内加入的物质是______________________。

②.设计2号试管作为对照的具体目的是_____________________。

③.如果2号试管未产生颜色反应,则出现橙红色沉淀的是____号试管。

考点:实验:比较过氧化氢在不同条件下的分解
题型:读图填空题

阅读理解。

     A long time ago, there was a huge (大的) apple tree. A little boy loved to come and play around it. He

climbed the tree, ate the apples… He loved the tree and the tree loved to play with him.

     Time went by…The little boy grew up and he no longer played around the tree.

     One day, the boy came back to the tree and looked sad. The boy told the tree that he wanted the toys

but he didn't have money. The tree asked the boy to pick all the apples and sell them. The boy did it and left

happily. He didn't come back after he picked the apples. Several years later, the boy returned again and said

he needed a house for his family. The tree asked the boy to cut off his branches (树枝) to build the house.

     Years later, the boy returned again. This time he wanted to go sailing but he didn't have a boat. The tree

said that the boy could use his trunk (树干) to make the boat. He went sailing and did not show up (露面)

for a long time.

     After many years, the boy returned. The tree said with tears, "Sorry, my boy. But I don't have anything

for you anymore. No more apples for you, No more trunk for you to climb on…Now the only thing left is

my dying roots (根)." "I don't have teeth to bite (咬) the apple and I am too old to climb the tree. I just need

a place to rest. I am tired after all these years," the boy replied. "Good! Old tree roots are the best place to

lean on (依靠) and rest. Come here, please sit down with me and have a rest." The boy sat down and the

tree was glad and smiled with tears… 

    This is everyone's story. The tree is our parent. When we are young, we love to play with Mom and Dad.

When we grow up, we leave them, and only come to them when we need something or when we are in

trouble. No matter what, parents will always be there and give everything they have to make us happy.

     You may think that the boy is cruel (残忍) to the tree but that's how all of us are treating (对待) our

parents.

1. How did the boy get the money to buy the toys? [ ]

A. By picking the apples and selling them.

B. By cutting off the branches and selling them.

C. By making money on his own.

D. By helping the farmers pick the apples.

2. What did the tree do when he knew the boy wanted a boat for sailing? [ ]

A. He asked the boy to cut off the branches to make a boat.

B. He asked the boy to use the trunk to make a boat.

C. He asked the boy to use the root to make boat.

D. He offered the apples to the boy and asked him to sell them

3. Put the pictures in the correct order according to the passage. The correct order is _______.

   

                   ①                       ②                                  ③                                   ④[ ]

A. ①③②④

B. ④①③②

C. ④②①③

D. ①④③②

4. Which of the following is NOT the writer's idea? [ ]

A. When children are young, they love to play with their parents.

B. When children grow up, they only come to them when they need something or they are in trouble.

C. Parents are always there and they are willing to (愿意) give everything to their children.

D. Children are always kind to their parents and they always like to stay with their parents.

5. The writer wanted to tell the children _______. [ ]

A. to protect the environment

B. to plant more trees

C. to treat their parents kindly

D. to stay at home with their parents

题型:读图填空题

与利尿药合用治疗急性肾功能衰竭的药物是()

A.去甲肾上腺素

B.多巴胺

C.麻黄碱

D.肾上腺素

E.可乐定

题型:读图填空题

下列关于铲装作业的描述正确的是()。

A、装车时铲斗可轻碰汽车车帮

B、运输设备不应装载过满或装载不均

C、应将大块装入车厢外侧

题型:读图填空题

加工斜齿轮时,刀具是沿齿轮的( )方向进刀的。

A.法线

B.齿线

C.轴线

题型:读图填空题

备用电源自投装置一般应满足哪些要求?

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