be difificult for sb do 还是doing还是to do只等15分钟

be difificult for sb do 还是doing还是to do只等15分钟 be sth for sb be vailable for sb. be true for sb. be down for sb be useful to sb还是for sb? be embarrassing to sb还是for sb? be important to sb还是for sb be rude to sb还是for sb be left for sb to be valuable for sb对吗 be important to sb.还是be important for sb.区别? 是be difficult to sb 还是be difficult for sb? be adj to sb 与be adj for sb 区别 be free to sb 还是 be free for sb ..快速.. be free to sb还是be free for sb 是be free to sb 还是be free for sb 什么时候be+形容词+for sb,什么时候be+形容词+to sb