【判断题】
理弧焊时,交流电源多用于大电流埋弧和采用直流时磁偏吹严重的场合。
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等离子弧的引弧频率一般为5000Hz。
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发生火灾,应迅速拔打火警电话"119"报警。
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凡进行登高作业和进入登高作业区域,焊工必须戴好安全帽。
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埋弧焊时电弧是在一层颗粒状的可熔化焊剂覆盖下燃烧,电弧不外露。
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严禁焊补未经安全处理或未开孔洞的密封容器。
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气焊、气割时,发生回火的根本原因,是混合气体的流速低于燃烧速度。
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焊接时局部振动对人体神经系统、心血管系统、肌肉和骨关节及听觉器官都会有损害,可能引血压、心率和脑血管血流图异常。
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焊条电弧焊可以在任何有电源的地方进行焊接作业。
【判断题】
气瓶运输(含装卸）时,轻装轻卸,避免剧烈震动,严禁抛、滑、滚、冲击,以防气体膨胀爆炸,最好备有波浪形的瓶架,垫上橡皮或其它软物,以减小震动。
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需要通水冷却的电渣焊用焊剂,可以不用烘干。
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焊条电弧焊时,有害物质的散发率随焊条直径减小而增加。
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氧-乙炔火焰中乙炔气体为可燃气体,氧气为助燃气体。
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将220V的变压器接到380V的电源上不会造成安全事故。
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堆焊在多数情况下,具有异种金属焊接的特点。
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焊接作业最常见危害也是最广泛的职业危害有电焊烟尘、有毒气体、电弧光辐射、高温。
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强度越高则金属材料抵抗变形和断裂的能力越大。
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— Fantastic! Nothing tastes ________.
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— Wow, _______! Will it pass our place?
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( ) 26. Where does the writer of "The little Prince" come from?
A．England． B．France． C．America． D．China．
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( ) 27. What does the prince do after the fox tells him a secret?
A．He cares more about a flower and a sheep．
B．He meets many more strange adults on other planets．
C．He realizes his love for the rose and he goes back to his planet．
D．He discovers interesting things such as a snake, other roses and a fox
【单选题】
( ) 28. What does "The little Prince" mainly talk about? It' s about _________．
A．the adult world B．the planet B -612
C．a rose and a fox D．the adventure of a young prince
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( ) 29. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
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( ) 30. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
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( ) 31. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
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( ) 32. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
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( ) 33. Why did Natalie Smith pay for the six cars behind her?
A. She had seven tickets.
B. She hoped to please others.
C. She knew the car drivers well.
D. She wanted to show kindness.
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( ) 34. Judy Foreman copied down the phrase because she ___ .
A. thought it was beautifully written
B. wanted to know what it really meant
C. decided to write it on a warehouse wall
D. wanted her husband to put it up in the classroom
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( ) 35. Who came up with the phrase according to the passage?
A. Judy Foreman. B. Natalie Smith. C. Anne Herbert D. Alice Johnson.
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( ) 36. What can we infer from the last paragraph?
A. People should practice random kindness to those in need.
B. People who receive kindness are likely to offer it to others.
C. People should practice random kindness to strangers they meet.
D. People who receive kindness are likely to pay it back to the giver.
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( ) 37.The greatest river for navigation is ___________.
A. the Nile B. the Amazon C. the Mekong D. the Mississippi
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( ) 38. From a dam, people can use the water for ___________.
A. keeping the rivers clean B. only making electricity
C. irrigation and making electricity D. washing clothes
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( ) 39. The water in the river is polluted because of _____________.
A. people's drinking water too much B. people's swimming in the river too much
C. chemicals and other materials D. people's building a dam across a river
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( ) 40. The best title of the passage is ___________.
A. Rivers in Cities B. The importance of Rivers
C. Transportation D. Natural Resources
