根据对话内容选择合适的答案填空。

A: Look, there are many animals in the zoo. Let's go and see them.

B: OK. Let's go.

A: Tom, there are so many birds in the tree.

B: Yes. There’s a monkey, too. I love monkeys.

A: There are two snakes under the chair.

B: Yes. But I don't like snakes.

A: Look, there are four chicks here.

B: How beautiful they are!

A: Two leopards are over there.

B: They are beautiful, too.

如图，抛物线y=﹣x²+bx+c交x轴于点A（﹣3，0）和点B，交y轴于点C（0，3）．

给画线的字选择正确的解释。

缘：①因由，原因 ②沿，顺着 ③因为 ④婚姻

只缘身在此山中____

他无缘无故的不上学了。____

缘木求鱼，不如退而结网。____