下列关于热学知识的说法正确的是（　　）

读图回答，目前人类活动对水循环的影响环节及办法主要表现在(　　)

    An artist went to a beautiful part of the country for a holiday, and stayed with a farmer. Every day he went out with his paints and brushes and painted from morning to evening, and then when it got dark, he went back to the farm and had a good dinner before he went to bed.
    At the end of his holiday he wanted to pay the farmer, but the farmer said, “No, I don't want money… but give me one of your pictures. What is money? In a week it will all be finished, but your painting will still be here.”
T    he artist was very pleased and thanked the farmer for saying such kind things about his pictures. The farmer smiled and answered, “It's not that. I have a son in London. He wants to become an artist. When he comes home next month, I'll show him your picture, and he will not want to be an artist any more, I think. ”

现代无机化学对硫﹣氮化合物的研究是最为活跃的领域之一．如图是已经合成的最著名的硫﹣氮化合物的分子结构．下列说法正确的是（　　）

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