a peg to hang on的用法和样例：
- He had not a peg to hang on and got dumb for some time.
- He has not a peg to hang on.
- She will use this as a peg to hang her grievance on.
- Dick is a talkative man, who merely wants a peg to hang a discourse on.
- There's a peg near the door to hang your coat on.