sb be interested in to do sth 这个是错的
正确的形式是sb be interested in doing sth
sth be interesting to do sth这个没有这种形式
人作主语sb be interested in doing sth 比如 I am interested in playing guitar.我对弹吉他很感兴趣.
物作主语 sth is interesting 比如：The game is very interesting.这个游戏很有趣.