题目内容：

根据句意用括号中单词的适当形式填空，使句子的意思完整、正确。

1.There are four ___________(season) in a year．

2.Birds are________ (sing) . They can make beautiful sounds.

3.It is sometimes ___________ (fog) in autumn and winter．

4.Birds in Zhalong are in _______(dangerous)．

5.Eddie, you used to share food with______( I )．