小型制冷装置制冷效果差是由于（）造成的 A.电源电压高 B.电源电压低 C.冷冻物品

发布时间：2020-12-09 12:55 │ 来源：www.tikuol.com

题型：单项选择题

问题：

小型制冷装置制冷效果差是由于（）造成的

A.电源电压高

B.电源电压低

C.冷冻物品少

D.制冷剂泄漏

考点：制冷设备维修工制冷设备维修工综合练习制冷设备维修工综合练习题库

题型：单项选择题

完形填空。

     Billy is a boy of fifteen. His parents died three years ago. One day when he was walking in the street,
he    1    a wallet. He returned it to the owner, Mr Baker. He gave his    2   to the boy. As the boy had no
job, Mr Baker made him work for him in his    3   . Billy worked so hard that Mr and Mrs Baker were    4
with him.
     Mr Baker loved planting    5 . The week before last, he brought a few trees home, planted them in the
6   himself and watered them every day. Several days    7 , he had to leave for another city. Before he
started, he said to Billy. "Take good care of the trees. Some boys near our house always want to steal (偷)
them." "Don't    8   about them, sir." answered Billy, "I'll try my best to watch them." Six days passed and
Mr Baker came back. He asked, "   9   anyone ever come to steal the trees?" "No, sir." Said Billy, "To stop
someone from stealing the trees, I   10   them up six days ago. I have hidden (藏) them for almost a week!"

( )1. A. found
(    )2. A. wallet
( )3. A. factory
(   )4. A. pleased
(   )5. A. flowers
(    )6. A. garden
(    )7. A. ago
(   )8. A. think
(   )9. A. Did
(   )10. A. sent

B. bought
B. pity
B. office
B. angry
B. grass
B. office
B. later
B. talk
B. Does
B. pulled

C. carried
C. thanks
C. town
C. strict
C. vegetables
C. city
C. before
C. learn
C. Has
C. put

D. wanted
D. excuses
D. home
D. popular
D. trees
D. room
D. after
D. worry
D. will
D. picked

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题型：单项选择题

阅读材料完成问题。

材料一：过去24小时空间天气综述：国家天文台在日面上观测到两个活动区,并且观测到一次C2.0级耀斑。

材料二：2011年8月9日北京时间16:05爆发一次X7.0级的软X射线耀斑，我国大部分地区短波吸收增加，对短波通信会产生严重影响，预计该影响会持续半小时左右。

小题1:太阳活动的平均周期约是

A．1年

B．11年

C．76年

D．60年小题2:材料一中，在日面上观测到两个活动区的主要判断依据是

A．黑子

B．耀斑

C．日珥

D．太阳风小题3:材料一中，观测到一次C2.0级的耀斑发生在太阳大气的

A．光球层

B． * * 层

C．日冕层

D．日珥小题4:材料二所述太阳活动对地球的影响表现在

A．在地球各地的夜空产生极光

B．使地球极昼极夜现象范围扩大

C．扰乱电离层，影响无线电短波通讯

D．使地球两极出现极昼和极夜现象

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题型：单项选择题

下列①②③④分别与相应的操作过程相对应，其中正确的是（　　）

A．①在恒温的条件下，将足量的氯化钠饱和溶液蒸发适量的水分

B．②向混有少量稀盐酸的氯化钙溶液中加入碳酸钠溶液

C．③向氢氧化钠溶液中不断加水稀释

D．④相同质量的且过量的锌粉和铁粉，分别与质量和质量分数相同的稀盐酸反应

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题型：单项选择题

关于菌斑说法正确的是

A．各部位菌斑结构无显著差异

B．同一口腔菌斑内细菌无显著差异

C．菌斑由粘性基质和嵌入其中的细菌构成

D．基质主要成分为唾液糖蛋白，细菌的胞内聚合物

E．在菌斑-牙界面层，细菌呈扇贝状直接附于釉质

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题型：单项选择题

比赛中一盘棋下完，裁判正在数子，应该：（）。

A、把棋子拨开

B、离开座位去玩

C、坐好看裁判数子

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