I don 't know the man． The man is talking with our headteacher（改为含有定语从句的复合句）
I don't know the man talking with our headteacher．
Lucy' s mother often makes her read English aloud at home．（改为被动语态）
Lucy is often made English aloud at home．
The old couple married thirty years ago．（改为同义句）
The old couple have for thirty years．
He used to go mountain climbing with his friends．（改为一般疑问句）
he to go mountain climbing with his friends？
The concert will start in half an hour．（对画线部分提问）
will the concert start？