题目内容：

根据句意，写出括号内所给单词的适当形式。

1.Good friends should share________ (happy) with each other.

2.The little dog grew up healthily under different mother________ (wolf) protection.

3.I like to go hiking and enjoy the beauty of the________ (nature) world.

4.As it was even________ (fog), it took me longer to get to school.