人们通过应用____，能够精确计算出地球的各种数据，证明地球是一个____的球体。

如图是某同学探究唾液淀粉酶对淀粉消化的实验操作过程，下列各项关于实验结果的描述中，正确的是（    ）

某书中有一方程$\frac{2+\square x}{3}=-1$，□被污渍盖住了，书后该方程的答案为x =－1，那么□处的数字应是(   ).

阅读短文, 下列问题

    Gladys Holm was a secretary(秘书). She worked in an office all his life. Gladys made about $15,000 a year. She died when she was 86 years old. And she left a big surprise—$18 million! She gave the money to a children's hospital.

    Gladys Holm never got married or had any children. But she always liked children, and she wanted to help them. When her friend's daughter was ill in hospital, Gladys brought her a toy bear. After that, she visited the hospital many times. Every time she visited, she brought toy bears for those children. After that, people started to call Gladys the "Toy bear Lady."

    Gladys always gave toys and presents to her friends and family but no one knew she had a lot of money. She lived in a small house outside Chicago. Everyone was very surprised when they learned she was a millionaire. A family friend said, "She always gave us nice presents and things, but we didn't know she was rich."

    How did Gladys get so much money? She asked her boss how to make more money, and she listened to what he said. She bought the stocks(股票) that he told her to buy, and she got very rich. Before she died, she talked to her friends about "giving something to the children's hospital." No one knew that the "something" was $18 million!