是be difficult to sb 还是be difficult for sb?

是be difficult to sb 还是be difficult for sb? be difficult to sb还是 be difficult for sb.? 到底该用哪个介词啊? 是be free to sb 还是be free for sb 英文语法：be sorry toor sb?是be sorry to sb还是be sorry for sb? be home to sb be surprised to sb? be happening to sb be dangerous to sb sb be prepared to be sth to sb be accountable to sb sb be honoured to leave sb doing /leave sb to do /leave sb to be done不好意思写错了~是leave sb done 是sb be the admitted to还是sb be admitted to?我又记错笔记了? be difficult to do是什么意思 prove to be difficult是什么意思? 是be up to sb to do还是doing? be attractive to sb此中的to是介词吗