It is hard of us to learn/of us to learning/for us to to learn/of us learning哪个对,为什么?

It is hard of us to learn/of us to learning/for us to to learn/of us learning哪个对,为什么? this question is very hard.None of us can work it out.(保持原意）this question is ______ hard for ________of us to work out it is adj of sb to do与it is adj for sb to do区别例题It is hard _______englishAof us to learn Bfor us to learn Cof us learning Dfor us learning It's hard for us to live in a （ ） country Beijing Opera is a symbol of Chinese( ) It is hard to 连词成句 is,English,if,us,hard,to,hard,learn,for,it,study,well,easy it is hard to think of a world without you It is very kind of you to come to us. work hard is of great important to us这句话中为什么有个of? It’s kind of you to think so much of us.It is not hard for one to do a bit of good.为什么一句用of而另一句用for It is hard to wait It is hard to please It is hard to select! It is i for us to finish this hard job in suth a short time It is necessary for us to work hard every day 同义句 It is hard for us to live in a______ country.这个空怎么填? 英语翻译：It is good of you to help us. It was _________(pleasure)for us to visit many places of interest of downtown,though it rained________(hard)at noon.