all of sudden对不对

正确是all of a sudden，例如：

1、All of a sudden someone grabbed me around the neck.猛不防有人抓住了我的脖子。

2、All of a sudden， right after the summer， Mother gets married.突然，刚过夏天，妈妈就结婚了。

3、All of a sudden she didn't look sleepy any more.她突然看起来一点都不困了。