题干

小华设计了如图1所示的甲、乙两种装置来探究“冰熔化时温度变化规律”.

①实验室常用温度汁是利用液体的____ 性质制成的,小华某一时刻观察到温度计示数如图2所示,该温度值为____℃.

②该实验应选用____(“大冰块’或“碎冰块”)来进行实验,效果更好些;

③为了使试管中的冰受热均匀.且便于记录各时刻的温度值,小华应选用图1中的____(“甲”或“乙”)装置来进行实验.

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答案(点此获取答案解析)

热胀冷缩,﹣2,碎冰块,乙

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    Spring is an inviting season for outdoor activities. But be careful—the warm weather is also a hotbed for viruses(病毒) and disease.  
This March, the influenza(流行性感冒) A(H7N9) virus hit Shanghai, Anhui, Jiangsu and Zhejiang. It was reported that by April 11 at least 35 people had been infected (被感染的) with the H7N9 virus, and nine of them had died.
    The influenza A (H7N9) virus is one type of influenza A H7 viruses. Influenza A H7 viruses normally spread among birds.
This is the first time human infections with H7N9 viruses have been reported in China. Earlier reports were about H5N1 and H1N1.
All the three viruses are influenza A viruses but they are not the same. H7N9 and H5N1 are animal influenza viruses that could infect people. However, H1N1 viruses can be divided into two groups. One group can normally infect people and the other normally infects animals. Also, H1N1 can spread from human to human, but H7N9 probably can't, according to the World Health Organization (WHO).
Most people infected with H7N9 looked like they had the common flu. Some people had bad pneumonia(肺炎). They suffered from a fever, a cough and shortness of breath.
    But don't be afraid – it is not easy to be infected with the virus. One of the possible reasons is close contact with sick poultry (家禽) waste. People may also be infected through breath, according to National Health and Family Planning Commission.
Here are some tips from the WHO that can protect you from being infected.
    Wash your hands with soap and running water before you eat, after you use the toilet, and after touching animals or animal waste.
When coughing or sneezing cover your mouth and nose with a mask(口罩),tissue(纸巾) or a sleeve.
    Get a good rest and do exercises, which will help make your body strong enough to stand up to the virus.