It is important _us _ study Euglish hard.A.to,to B.for,to C.at,to D.for,at但我不知道为什么.

It is important _us _ study Euglish hard.A.to,to B.for,to C.at,to D.for,at但我不知道为什么. it is very important how important it is 还是how important is it It is a important problem Nothing it is Nothing it is important是什么意思 Nothing it is important是什么意思 Nothing it is important是什么意思 it is important to it is important for it is important of 这三个结构都有吗 都怎么用 it is very important to people How important it is _____ (save) water! why is it important to speak English? it is important 最高级形式是什么 It is important to be careful with is it important to look good?why? 对because it is very important提问 It's happy is very important! It is an important festival in theWest. just like 和 It is important to It is important that 后面怎么跟 is it important换成两个词