根据句子的意思或者是括号内的提示完成句子。

1. The best part of the trip was the scenery. It was f _____.

2. They have a _____ (可爱的) son Sam. Sam is the honey of the whole family.

3. He helped me with my English; in return, I gave him the best _____ (礼物).

4. He knows the _____ (意思) of the words he reads.

5. Many people want to send their children a _____ to be educated.

简述什么是水平迁移与垂直迁移。