根据短文内容，在下面句子中的空格中各填上一个合适的单词。

     I am an apple. You can find me all around the world. I am not like my brother-pear. I am rounder (更圆). I am not like my sister-banana either (也). She is longer (更长). I am delicious, so people all over

the world like to eat me. I am very cheap and I can keep people healthy. There is an old English saying

(谚语): An apple a day keeps the doctor away.

1. The apple's brother is ________.

2. Banana is the apple's ________.

3. Apples are ________, so we like to eat them.

4. There is an old ________ saying.

5. An apple a day keeps the ________ away.