印度尼西亚能源丰富，石油、天然气、煤炭等大量出口。该国巴厘岛是国际旅游胜地，每年接待游客过千万，但却仅依靠岛上一座燃气电厂和海底电缆供电，电力长期供应不足。

    2015年，由中国某公司投资、建设并运营(运营满30年后无偿移交印尼)的巴厘岛燃煤电厂投入使用，发电量占巴厘岛电力供应的40%，极大缓解了巴厘岛电力紧张状况。该项目使用我国高效的清洁燃煤技术与多项环保技术，实现清洁生产。该公司为当地提供几千个就业机会，还帮助当地修建学校、村公所等。下图示意该燃煤电厂位置。

学习的目的是在于应用．请根据你所掌握的化学知识，解释或解决以下生活中的一些常见问题．

（1）金刚石和石墨物理性质不同的原因是 ____；

（2）要区分一氧化碳和二氧化碳两种无色气体，可采用的方法是 ____；（写一种即可）

（3）为保证人身安全，进入久未开启的菜窖前，须做 ____试验；

（4）北宋画家张择端用墨绘制的《清明上河图》能够保存至今，是因为 ____

根据短文内容, 选择正确答案。

    If you go into the forest with friends, stay with them. If you don't, you may get lost. If you get lost, this is what you should do. Sit down and stay where you are. Don't try to find your friends. Let them find you. You can help them find you by staying in one place. There is another way to help your friends or other people to find you. You can shout or whistle three times. Stop. Then shout or whistle three times again. Any signal given three times is a call for help.

    Keep up shouting or whistling. Always three times together. When people hear you, they will know that you are not just making a noise for fun. They will let you know that they have heard your signal. They will give you two shouts or two whistles. When a signal given twice, it is an answer to a call for help.

    If you don't mind that you will get help before night comes, try to make a little house with branches. Make yourself a bed with leaves and grass.