同义句转换：1.He was a teacher in the past,but now he isn't.He___ ____ ____ a teacher.
2.It seemed that she has changed a lot.
She seemed to___ ___ a lot.
3.He's been singing for five years.
He began to sing___ ___ _____
4.Unless we deal with our problem,we can easily become unhappy.
___we___ deal with our problem,we can easily become unhappy.
5.It seems that Yu Mei has changed a lot.
Yu Mei seems quite ___ ___the past.