根据句子意思及汉语提示，写出所缺的单词。

1. Susan plays the piano very _________ (好).

2. Have you ever _________ (骑) a horse?

3. I'm sure your cousins can do these exercises _________ (自己)

4. I love children, _________ (尤其,特别) when they smile.

5. My brother sleeps with the window open _________ (除非) it's really cold.