完形填空。从A、B、C、D四个选项中选出最佳答案。

    Mr. Smith lived in a village（村庄）. He had a few farms（农场） and about twenty people working for him. He often told them 1hard and be honest(诚实的).

    One day he went to a farm and worked with the workers there. Soon it was time 2 lunch. He put 3 nice bread on the table and went out. A few minutes later, he came back again but he couldn't find the bread. "Who ate 4 on the table?" he shouted.

    Some of the workers answered, "We didn't."  The others said, "We saw nothing."

    "Well," said Mr. Smith, "5 are a lot of mice(老鼠) in the rooms, you know. So I put some poison（毒药） in the bread. 6 they eat, they must die. Then I can kill them."

    As soon as he finished, four workers began to cry. "Oh, dear!"

    "7?" asked Mr. Smith.  "We ate the bread when you were out. We are going to die." One of them cried.  "8," Mr. Smith said 9 a smile, "I only 10 you. Use your head."

在$△ABC$中,$\overrightarrow{AB}+\overrightarrow{AC}=2\overrightarrow{AM}$， $\left|\overrightarrow{AM}\right|=1$,点P在AM上且满足$\overrightarrow{AP}=2\overrightarrow{PM}$,则$\overrightarrow{PA}·\left(\overrightarrow{PB}+\overrightarrow{PC}\right)$等于(   )

在我们生活的环境中，存在着大量的细菌和真菌，下列相关的叙述中，正确的是（    ）

在《秦王扫六合》一课的讨论环节中，某学习小组的同学就“分封制”和“郡县制”进行了激烈争论，下列观点正确的是（    ）