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问题 问答题

某同学为探究动物的呼吸作用，如右图所示（实验装置足以维持实验过程中小白鼠的生命活动，忽略水蒸气和温度变化对实验结果的影响），数小时后发现______，U型管内的液面A处______（填“上升”或“下降”），B处______（填“上升”或“下降”）．实验结束后，将燃着的木条伸入瓶中，发现______．该实验说明动物吸入______（填气体名称），呼出______（填气体名称）．

答案

小白鼠呼吸吸收氧气呼出二氧化碳，氧气被小白鼠吸收掉，石灰水吸收了二氧化碳故容器内气体压强变小，U形管内液面会有变化A处上升B处下降

故答案为：澄清石灰水变浑浊，上升，下降，木条熄灭，氧气，二氧化碳．

单项选择题

I got a job teaching special education at a school in Coachella, California, a desert town about 170 miles from home. It was no (1) job. Street gangs (2) around the school after dark.

"Be careful, " Dad warned me during one of my frequent weekend (3) home. He was concerned about my living (4) , but I needed to be on my own.

One evening, I stayed after school to rearrange my classroom. (5) , I turned out the light and closed the door. Then I (6) toward the gate. It was (7) ! I looked around. Everyone had gone home.

After (8) all the exits, I found just enough (9) to squeeze under a gate in the back of the school. Then I walked toward my car, parked in a field behind the building.Suddenly I heard voices. I (10) around and saw at least eight boys following me. (11) my pace, I reached into my shoulder bag to get my key. I (12) all over the inside of my handbag. But the key wasn’t (13) ! Dear Lord, please help me, I prayed (14) . Suddenly, my fingers touched a loose key in my purse. I didn’t even know if it was for my car, but I took it out and (15) it. It worked!I opened the door, slid in and locked it—just (16) the teenagers surrounded the car. Trembling , I started the engine and (17) away. When I returned to my apartment, the phone was ringing. It was my Dad. I didn’t tell him about my experience; I didn’t want to (18) him. "Oh, I forgot to tell you!" He said, "I had a (n) (19) car key made and slipped it into your purse—just (20) you ever need it.

2（）

A.came 

B.robbed 

C.hung 

D.fought
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单项选择题

投保机动车辆附加盗抢险的车辆，在停放中被窃，经出险当地县级以上公安刑侦部门立案证明，满（）天未查明下落的，保险人负责赔偿。

A.90

B.60

C.30

D.45
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