鳞状细胞癌起源于（） A.主支气管黏膜上皮细胞 B.小支气管黏膜_爱下问搜题

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问题单项选择题 B型题

鳞状细胞癌起源于（）

A.主支气管黏膜上皮细胞

B.小支气管黏膜上皮细胞

C.支气管腺体

D.Ⅱ型肺泡上皮细胞

E.Kulchitsky细胞

答案

参考答案：A

选择题

用18mol/L 浓硫酸配制100 ml 3.0mol/L 稀硫酸的实验步骤如下：

① 计算所用浓硫酸的体积 ② 量取一定体积的浓硫酸 ③ 溶解

④ 转移、洗涤 ⑤ 定容、摇匀

回答下列问题：

（1）所需浓硫酸的体积是 mL ，量取浓硫酸所用的量筒的规格是。

（从下列中选用 A. 10mL B. 25mL C. 50mL D. 100ml）

（2）第③步实验的操作是

。

（3）第⑤步实验的操作是

。

（4）下列情况对所配制的稀硫酸浓度有何影响？（用偏大、偏小、无影响填写）

A. 所用的浓硫酸长时间放置在密封不好的容器中

B. 容量瓶用蒸馏水洗涤后残留有少量的水

C. 所用过的烧杯、玻璃棒未洗涤

D. 定容时俯视溶液的液凹面

单项选择题

D

What are you going to do if you are in a burning house How will you escape Do you know how to save yourself Please read the following passage.
Escaping a fire is a serious matter. Knowing what to do during a fire can save your life. It is important to know the ways you can use and show them to everyone in the family, such as stairways and fire escapes, but not lifts.
From the lower floors of the buildings, escaping through windows is possible, learn the best way of leaving by windows with the least chance of serious injury.
The second floor window is usually not very high from the ground. An average(平均高度的) person, hanging by the finger-tips will have a drop of about six feet to the ground. It is about the height of an average man. Of course, it is safer to jump a short way than to stay in a burning building.
Windows are also useful when you are waiting for help. Be sure to keep the door closed. Or smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get fresh air rather than smoke that may leaked (渗) into the room.
On a second or third floor, the best windows for escape are those that open onto a roof. From the roof a person can drop to the ground more safely. Dropping onto cement(水泥) might end in injury. Bushes(灌木丛) and grass can help to break a fall.

Open the window so that ______ if the building is on fire.

A．you can get fresh air

B．you can call for help

C．you can easily jump off

D．you can be seen first