问题 实验题

(5分)阅读材料,回答问题。

材料一 今年4月我市一家歌厅发生火灾,事故的原因是电线起火,引燃了聚氨酯泡沫塑料天花板,造成了一定的财产损失。

材料二 氢氧化铝Al(0H))3是一种无机阻燃剂。当温度达到25O℃时,氢氧化铝开始分

解出水蒸气和耐高温的氧化铝固体颗粒。利用氢氧化铝的这一性质,将它添加在塑料等易

燃材料中起到阻燃作用。

(1)聚氨酯塑料泡沫属于        材料(填“有机”或“无机”)

(2)起火的电线在火灾中起到的作用是            (填序号)。

A.提供可燃物    B.使可燃物达到着火点    C.提供氧

(3)根据灭把原理分析氢氧化铝作阻燃剂的原因                                      (答一点);

氢氧化铝分解的化学方程式为                                       

答案

(l)有机  (2)B  (3)①分解吸热,抑制塑料升温。?分解生成的水蒸气起到了既冷却又稀释的效果,阻止燃烧进行。③分解生成的氧化铝颗粒附在可燃物表面,阻隔空气,

阻止燃烧。2Al(OH)3Al203+3H2O    (前三个空各l分,方程式2分,共5分)

:(1)聚氨酯塑料是塑料的一种,应属于有机合成材料,因此判断其为有机材料;

(2)起火的电线引燃其它可燃物而引发火灾,因此可判断在火灾中起火的电线起到了使可燃物达到其着火点的作用;

(3)氢氧化铝分解时吸收热量,分解出的水蒸气蒸发时也可使大量热量及时散失,这都可使塑料的温度不易达到其着火点而不能燃烧;分解出耐高温的氧化铝固体颗粒也可以阻止塑料与空气中氧气的接触,有效地防止燃烧的发生;分解的化学方程式为2Al(OH)3Al203+3H2O;

故答案为:

(1)有机;

(2)B;

(3)氢氧化铝分解吸热,抑制塑料升温(或分解生成的水蒸气起到冷却的效果,阻止燃烧进行;或分解生成的氧化铝颗粒附在可燃物表面,阻隔空气,阻止燃烧);2Al(OH)3Al203+3H2O.

阅读理解

Speak, speak, speak!

Practise speaking as often as you can. Speaking to yourself is good practice.

Try recording yourself whenever you can.

Compare your pronunciation with the master version(原版)to see how you can do better and have another go. If you do this several times, you will find that each time is better than last.

Why not learn with someone else?

It helps if you can learn with someone else. If you can persuade a friend or family member to study with you, it will make you keep working.

Don't get stuck by a word you don't know.

Practise improving ways of getting your meaning across when speaking spontaneously(本能地),even if you don't know the exact words or phrases. Think of things you might want to say whenever you have spare time. Use facial expressions, hand movements, anything to make yourself understood.

Language learning is also about intuition(直觉).

Guesswork is an important way to learn a new language. When listening to recorded material, you aren't expected to understand everything first time round. If you play the same piece several times, you will most probably understand something new each time.

Build up your vocabulary.

A wide vocabulary is the key to successful language learning but don’t try to learn too much at once. It’s best to study frequently, for short periods of time. Take at most six or seven items of vocabulary and learn them. Put them into sentences to fix them in your mind, and then come back to them later.

And above all, have fun!

小题1:  What’s the purpose of this passage?

A.To tell us the importance of practicing speaking as often as we can.

B.To tell us a few tips to help us learn a new language well.

C.To tell us that guesswork is an important way to learn a new language.

D.To tell us that a wide vocabulary is the key to successful language learning.小题2: What’s the meaning of the underlined phrase in the first part?

A.Have another try or attempt.

B.Move away from a place to another.

C.Enter a certain state or condition.

D.Follow or take a certain course.小题3:  To learn English well, we shouldn’t _______ according to the passage.

A.practice speaking as often as possible

B.study frequently, for short periods of time to build up our vocabulary

C.try to understand everything and stop when we meet a new word

D.try to persuade a friend or family member to study with us小题4: According to the passage, to learn a new language well, the most important thing is ______.

A.speaking as much as possible

B.having fun

C.a wide vocabulary

D.guesswork

选择题