write a song的用法和样例：
- To write a melody for(a song lyric).
- Man could that old Bub write a song!
- Robbie: I wrote a song about you.
- Wu Yue Cheng is very quick. He can write a song in a meal's time.
- The whole reason you write a song is so you don't have to talk about.
- From now on you will live with me in my heart and in my song. My harp will play for you, and I will write a song describing your death.