thank sb for sth/doing sth感谢某人做某事,这里thank是及物动词,不用thank for sb,也不能直接thank for sth.
thanks to sb/sth多亏了某人/事,其实跟谢谢是一样的,或者thanks for sth,这里的thank是可数名词.
单是谢谢某人的话,可以说many thanks to sb.