题干

某科学兴趣小组的同学在探究“土壤中含有机物”时,采用了下列三种方法得到干燥的土壤:①长期日晒;②在高温火焰上长时间烧烤;③恒温箱内烘干。他们在实验过程中总结出以下规律:土壤在加热过程中,一些小分子的有机物在加热时会直接燃烧生成CO2和H2O,而大分子的有机物在加热时先炭化分解成碳,碳再燃烧生成CO2

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    Today.an increasing number of people are always looking at their mobile phones with their heads down. These people are called the " Heads-down Tribe (低头族)". Are you a head-down tribe member? Heads-down tribe members now can be seen everywhere.

More and more traffic accidents are happening because more drivers use mobile phones when they are driving. In order to make drivers pay more attention to driving, some new traffic rules have been made. For example, people who use mobile phones while driving in Taiwan are fined(罚款). Car drivers and motorcyclists who break the traffic rule will be fined NT$ 3,000 and NT$1,000 respectively(分别地)

As we can see above, using mobile phones may cause accidents and even cost a lot of money. Also,more and more interesting and strange facts happen to the "Heads-down Tribe". Let's have a look at an interesting TV report. A man in America kept using his mobile phone on his way home. As a result, he knocked into a big lost bear. When he lifted his eyes from the phone, he was so afraid that he turned around and ran away quickly. Another fact is that we can often see people in the restaurant eating face to face but looking at their own mobile Phones. It's strange that they don't talk to the ones who sit opposite to them during the meal. Some of them even have fun communicating with others on the phone.

    Mobile phones are helpful and necessary tools for modern life. Are mobile phones good or bad? It depends on how people use them. Let's be "healthy" users and try to be the "Heads-up Tribe".