生物圈包括____ 的底部、水圈的大部和____ 的表面．

将8.1g氧化锌固体放入100g稀硫酸中，恰好完全反应．试计算：
①可生成硫酸锌多少克？
②所用稀硫酸的溶质质量分数是多少？（化学方程式：ZnO+H₂SO₄=ZnSO₄+H₂O）

B

    Chris and Jessica live in Miami，Florida.They are packing(收拾行李)now.They're going away for a three-­week vacation tomorrow.They're going to rent(租)a house near a small lake about 100 miles north of the city.

    Chris is a carpenter(木匠)and he works hard.He often works ten hours a day，and he makes good money.He helps to build and repair houses.He likes his job and Miami.

    Jessica spends a lot of time working in her office and taking people to see houses.Her job and her family keep her busy.She gets little time to read and relax during the year.

    Chris and Jessica enjoy the quiet of the country.Chris loves fishing.He is going to rent a boat and he will go fishing on the lake for four or five hours every day during the vacation.

    Jessica doesn't like fishing，but she's an excellent swimmer.She is going swimming every afternoon during the vacation.After that，she will sit in the yard and read for a few hours.She especially likes to read novels.

Both Chris and Jessica believe that they will have a great time there!