题干

电影《黄金大劫案》上映后,里面用“王水”(浓盐酸与浓硝酸的混合液)溶解黄金的情引起了广泛的热议。黄金溶解在“王水”中形成HAuCl4(四氯合金酸),没有氢气产生。根据以上信息,下列有关说法正确的是(   )
①“王水”溶解黄金是化学变化;②金比氢活泼;③HAuCl4中,Au的化合价为+3价;④可以将pH试纸伸入“王水”中测其酸碱度;⑤“王水”可以用铁质容器盛装。  

A:①④⑤

B:①②③

C:③④⑤

D:①③

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D

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    In the eyes of many foreigners, Chinese are the best hosts (主人) and the worst guests in the world. They're not really bad guests, but because the guest-host relationship in China is much different than in some western counties, it appears they are not nice guests. And western guests sometimes look rude (粗鲁的) in the eyes of Chinese guests.

    In China, guests are almost like gods. Whenever I enter a Chinese person's home, there is always fruit on the table for me, and someone is quick to bring me a cup of tea or water. In the west, generally the guest is not a god. Acting according to the host's way of doing things is usual behavior for a guest.

    My wife's mother, a very kind elderly Chinese lady, doesn't smoke. When I see some of her guests smoking in her house, as a non-smoker, I feel unhappy. Usually I want to stop them directly, but I must realize that in China, to be a good host, she must not do that. In most North America homes, if you are a guest, and the hosts are not smokers, you should not smoke in their house. At the very least, you could ask, “Is it OK if I smoke?” “But, don't be surprised if they say, “No, you can't smoke.” In our culture, if you smoke in their home, you are a bad guest, but if they don't allow you to smoke in their house, they are not a rude guest.

    Guests in China also have special habits. Some western people may not adapt to these habits very soon. Thankfully my wife is Chinese, so whenever we visit a Chinese family she tells me to buy them a gift. However, giving a gift to a host is not always necessary in my country. So, if you invite international guests to your home, don't be too surprised if they don't bring you a gift.

    In China, you probably won't need to change the guest-host relationship very much because you will probably only be the host, and Chinese are naturally very good hosts. If western hosts invite you to their house, try not to be too surprised if their style of treating you is not what you have expected.