题目内容：

用方框中所给单词的适当形式填空，每词仅用一次。

1.Teachers often tell their students about the _________ of learning how to learn.

2.Kathy is an _______ and friendly girl, her teachers all like her.

3.I prefer lemons to apples. I like the sour _________.

4.Think it over before you make a ________.

5.We were _________ into four groups by Mr. Zeng at the beginning of the game.