a one meaning in Chinese

Examples

1. He's such a one to sing, i can tell you !
   我告诉你，它很会叫呢！
2. The meals there are a one .
   那里的饭菜是第一流的。
3. He is a one , your son . never out of trouble !
   你的儿子真是个活宝。没有一会儿不惹麻烦的！
4. You asked your teacher how old she was ? you are a one !
   你问老师她有多少岁了？可真有你的！
5. Oh ! you are a one , telling that joke in front of the priest .
   你敢在牧师前这样开玩笑，真了不起。