双边会谈中，通常用长方形、椭圆形或圆形桌子，宾主相对而坐，以正门为准，主人应坐在哪一

做完“铁在氧气里燃烧”实验后，某兴趣小组有一些疑惑不解的问题，于是他们进行了以下探究活动，请你一同参与。

[问题1] 细铁丝在氧气中燃烧为什么会“火星四射”?

[查阅资料1]①日常生活中的钢铁制品都含有少量碳杂质。 ②含碳细铁丝燃烧时，其中的炭粒生成的CO₂气体在熔融液态物质中形成气泡，熔融液态物质因气泡炸裂引起“火星四射”的现象。

[设计实验]为了探究细铁丝在纯氧中燃烧产生“火星四射”现象的原因，该小组同学设计的实验方案是：取长短粗细相同的含碳细铁丝和不含碳的细铁丝，分别在足量的氧气中燃烧，观察现象。你认为他们的方案         （填“合理”或“不合理”）。

[实验探究1]小明做细铁丝在氧气中的燃烧实验时，他把细铁丝绕成螺旋状，一端系在一根铁丝上，另一端系上一根火柴。点燃火柴后迅速把铁丝连同火柴一起插入集气瓶下部（没有接触到细沙，如图所示），但不见铁丝燃烧，反复实验均未成功。

该同学认为可能导致失败的原因主要有三种：

A．铁丝表面有锈迹，影响了反应的进行；

B．点燃火柴后立即将它伸入瓶内，火柴燃烧消耗了氧气，不利于铁丝的燃烧；

C．火柴燃烧时有大量的热量放出，将铁丝和火柴迅速伸至集气瓶下部，因热胀冷缩之故。瓶内氧气会膨胀逸出，使铁丝无法燃烧。

实验：根据以上假设，他对实验应作的相应改进为：

(1)         ；(2)          ；(3)            。

[问题2]铁燃烧时溅落下来的黑色物质中还有没有铁呢？

[查阅资料2] ①自然界中铁的氧化物主要是Fe₃O₄和Fe₂O₃两种（FeO极易被氧化为Fe₂O₃）；②铁的氧化物均能溶于酸的溶液。

[实验探究2]将冷却后的黑色物质碾碎，装入试管，加入_____溶液，观察到的现象是_____，说明铁燃烧时溅落下来的黑色物质中还含有铁。

[问题3]铁燃烧的产物为什么不是Fe₂O₃呢？

[查阅资料3]①Fe₃O₄和Fe₂O₃的分解温度、铁的熔点见表：②Fe₂O₃高温时分解成Fe₃O₄。

根据实验现象，并结合表中数据，可推知铁在氧气里燃烧时产生的高温应在_____之间，在此温度范围内Fe₂O₃已分解，所以铁在氧气里燃烧的产生是Fe₃O₄。

[拓展延伸]

（1）小林同学发现“铁丝”在纯净氧气中燃烧起来，观察到火星四射，并有黑色固体生成，请写出该反应的化学方程式      ；

（2）Fe₂O₃高温时会分解成Fe₃O₄和一种气体，请写出此反应的化学方程式__________；

（3）有些超市的食品密封包装盒的透明盖内放有黑色的FeO粉末，若粉末的颜色_____，就说明包装盒破损进气，这样售货员就能及时发现并处理。

提单的种类有______。

A．已装船提单

B．收货备运提单

C．记名提单

D．指示提单

E．不记名提单

关于抑制性突触后电位产生过程的描述，错误的是（）

A.突触前轴突末梢去极化

B.Ca²⁺由膜外进入突触前膜内

C.突触小泡释放递质，并与突触后膜受体结合

D.突触后膜对Cl^-或K⁺的通透性升高

E.突触后膜膜电位增大，引起突触后神经元发放冲动

下列何项不是六味地黄丸的药组( )

A．丹皮

B．泽泻

C．枸杞

D．淮山

E．茯苓

The appeal of advertising to buying motives can have both negative and positive effects.

Consumers may be convinced to buy a product of poor quality or high price because of an advertisement. For example, some advertisers have appealed to people’s desire for better fuel economy for their cars by advertising automotive products that improve gasoline mileage. Some of the products work. Others are worthless and a waste of consumers’ money.

Sometimes advertising is intentionally misleading. A few years ago a brand of bread was offered to turned out that the bread was not dietetic (适合节食的), but just regular bread. There were fewer calories because it was sliced very thin, but there were the same number of calories in every loaf.

On the positive side, emotional appeals may respond to a consumer’s real concerns. Consider fire insurance. Fire insurance maybe sold by appealing to fear of loss. But fear of loss is the real reason for fire insurance. The security of knowing that property is protected by insurance makes the purchase of fire insurance a worthwhile investment for most people. If consumers consider the quality of the insurance plans as well as the message in the ads, they will benefit from the advertising.

Each consumer must evaluate her or his own situation. Are the benefits of the product important enough to justify buying it Advertising is intended to appeal to consumers, but it does not force them to buy the product. Consumers still control the final buying decision.

The passage tells us that ().

A. sometimes advertisements really sell what the consumer needs

B. advertisements occasionally force consumers into buying things they don’t need

C. the buying motives of consumers are controlled by advertisements

D. fire insurance is seldom a worthwhile investment