将下列句子改为间接引语13.His father said to him,"Think,before you do it

将下列句子改为间接引语
13.His father said to him,"Think,before you do it!"
14.The teacher said to his students,"Tell briefly in your own words how penicillin was discovered."
15.The leader said to him,"Please write your report as short as possible."
16.He said to me,"Let me have a look at the book you bought."
17.He said,"I am proud of my motherland."
18.John said,"I wrote back telling him about it yesterday."
19.I said,"I will give her some advice tomorrow."
20."You are wasting your time day-dreaming!" he said to Mary.
21."You have already done your duty," he said to her.
22.Mary wrote in her letter,"Mr.Liu,when will you come to America?"
23."Don't risk your lives,men!" the captain warned.
24."I'll be very busy today," said the man.
25.She said,"We have worked on the school farm for two weeks."