Most people drink tea in the world. But tea does not mean the same thing to different people. In different countries, people have different ideas about drinking tea.

    In China, for example, tea is often served when people get together. Chinese people drink it at home or in tea houses at any time of the day. They often use hot water to boil tea leaves.

    Tea is also important in other Asian countries. People in these countries have a special way of serving tea. They hold a tea ceremony in their houses when important guests come. It is very old and full of meaning. Everything must be done in a special way in the ceremony. There is even a special room for it in their houses.

    In the United States, people usually drink tea at breakfast or they drink it after meals. Americans usually use tea bags to make tea. This way is faster and easier than the way of making tea in teapots. In summer, most Americans drink iced tea. They like to put some ice in their tea.

有关CuSO₄制备途径及性质如图所示．

已知：

①Cu+2H₂SO₄（浓） CuSO₄+SO₂↑+2H₂O．

②在一个化学反应中，如果有元素化合价升高，同时就有元素化合价降低．下列说法不正确的是（　　）