根据句意及汉语提示完成句子。

1. There has been not much _____ (疾病) in the village this winter. The villagers are all healthy.

2. Nothing will _____(阻止) us from reaching our aims.

3. It's snowing hard. The ground is _____ (覆盖) with snow.

4. Take this _____ (药) ,and have a good rest, you can feel better.

5. I _____ (猜想) you don't agree with me.

6. Can you tell me the _____(差异) between the two words, Tom?

7. I have been there many times in the _____ (过去).

8. Computer was invented in 1946. It _____ (改变) a lot all over the world.