1.I have learned （）most of the students are interest in Chin

1.I have learned （）most of the students are interest in Chinese.
aWhether,B If cThat d Which
2.a.Have sold.b.Sold.C ,sells.d.sell
She is a famous writer,all of her books （） well.
3.It （）ten years since he（） an actor.
a,IS,has been.b.Has been,became.c.Was,became.d.Has been,has become.请说下原因,