根据句意和首字母提示，用单词的正确形式填空。

1. Danny f_______ off his bike yesterday.

2. On my birthday p_______ my friends sing many songs for me.

3. Spring Festival and National Day are important h_______ in China.

4. We sing special s_______ on Christmas.

特大暴雨的标准是日降雨量达到：（）。

A.50毫米以上

B.100毫米以上

C.250毫米以上