单词拼写。

 根据句子意思和汉语提示，写出空缺的形式正确的单词。

1. The third, the Vikings, _______(影响)the vocabulary and place-names of the North of England, and the

    fourth, the Normans, left castles and introduced new words for food.

2. John Snow suggested that the source of all the water supplies be _______(检查)

3. So many thousands of terrified people died every time there was an ________(爆发).

4. The problem ______(出现) because astronomers had noticed that some planets in the sky seemed to stop,

    move backward and then go forward in a loop.

5. His friends were ________(热情的) and encouraged him to publish his ideas.

6. Well,you have to listen for the detailed facts. _______(同时)you have to prepare the next question

    depending on what the person says.

7. The president of the university _______(批准) his appointment to the department two days ago.

8. The workers are ________(乐观) about the future of their factory.

9.You have three layers of skin which act as a _______(屏障) against disease.

10. People at a much later date who write about the same events are called secondary______(来源).