患者女性，60岁，3小时前胸骨后压榨样疼痛发作，伴呕吐、冷汗及濒死感而入院。护理体检

如图是多用表的刻度盘，当选用量程为50mA的电流档测量电流时，表针指于图示位置，则所测电流为______mA；若选用倍率为“×100”的电阻档测电阻时，表针也指示在图示同一位置，则所测电阻的阻值为______Ω．如果要用此多用表测量一个约2.0×10⁴Ω的电阻，为了使测量比较精确，应选的欧姆档是______（选填“×10”、“×100”或“×1K”）．换档结束后，实验操作上首先要进行的步骤是______．

London has always been known for its "black fogs". In the winter of 1952, a milky white fog rolled into the city. As the smoke poured into the air, it was so hard to see that people had to walk in front of the buses to guide them. In this way, the most serious air pollution disaster in history began. When it was over, more than 4,000 people had been killed by the thick black smog.

New York City has had several London-type smogs since 1950. Each time, 100 to 400 deaths were caused by the smog. Although these smogs were not as deadly as London's, New York City has the worst air pollution problem in the United States.

In all the killer smogs, factories and homes poured smoke and fumes into the air from the furnaces. The chemical fumes combined with the water droplets in the fog to form harmful substances. These substances caused the illness of those who breathed the polluted air.

Usually, such harmful fumes rise into the upper air and are blown away by the wind. But sometimes there is an unusual weather condition called a temperature inversion. A layer of cold air remains near the ground as smoke and fumes pour into it. This is covered by an upper layer of warm air that acts like a lid. It prevents the polluted cooler air from rising. The harmful fumes pile up and make people ill. The smog may be so thick that airports are closed and chains of collisions occur on the highways.

Another type of smog occurs in Los Angeles. Here the weather may be clear and sunny. But stinging eyes and dry coughs show that harmful chemicals fill the air. The smog is due to invisible gases, mostly from automobile exhaust. Because these chemicals are changed by the sun high up in the air, it is called photochemical smog. It contains automobile exhaust fumes and nitrogen oxides changed by the sun's rays. Added to these are sulfur dioxide and other fumes from factories and oil refineries. Photochemical smog is found in many large cities all over the world.

Killer smogs don't happen very often, fortunately. But in Beijing, a combination of automobile exhaust fumes, home furnace smoke, and factory waste gases pours into the air. This may also happen in the suburbs, or out in the country, where large factories have been built. A number of harmful substances have been found in the air there. When these substances are breathed in day after day, the health of the population is affected.

小题1:Why do people call this phenomenon "black fog"?

A．It is black and dirty.

B．It can affect the health.

C．It can kill people.

D．It is too thick for people to see something.小题2:What can reduce the air pollution according to the passage'?

A．Water.

B．Wind.

C．The sun.

D．Cold air.小题3:When photochemical smog happens in the city,          .

A．many people will be killed

B．black smoke may pour into the air

C．the weather may be fine

D．people have to walk to work小题4:From the passage we know that the most serious black smog disaster took place in    .

A．London

B．New York

C．Los Angeles

D．Beijing

男孩，2岁。因发热3d，呕吐2次，烦躁、多汗。昨晚突然哭声嘶哑，吃奶呛，随后吞咽困难，同时伴右下肢不能站立及行走来院就诊。体检：体温38．2℃，神志清，烦躁，咽反射消失，颈轻抵抗，心、肺无异常，腹软，右下肢肌力Ⅰ～Ⅱ级，腱反射消失，无病理反射。患儿未服过脊髓灰质炎疫苗糖丸，诊断为脊髓灰质炎。

该病儿应是脊髓灰质炎的（）

A.脊髓型

B.脑炎型

C.脑干型

D.混合型

E.脊髓胸颈段联合型

门位置传感器故障可行补救方法是（）。

A.门驱动电机启动（开门或关门方向）

B.在门运动过程中，没有来自门位置传感器各相的计数脉冲

C.如果门位置传感器各相均有不少于一个的计数脉冲

D.检查门位置传感器和EDCU的输入电路

下图表示一生态系统中生物种类间的相互关系，图中各种类均生活在退潮后暴露出的岩石上，其中海藻、藤壶、贻贝和海葵固着于岩石表面，海星、石鳖和石械则在岩石表面来回爬动找寻食物，图中的数字表示海星食物中各种类所占的比例（%）。

此图若添加（）成分，可构成完整的生物群落，再加上（）就可以构成一个生态系统。