It’s necessary us English well.
A. for , to learn
B. for , learning
C. of , learning
D. of , to learn
网友回答
(答案→)A. for , to learn
B. for , learning
C. of , learning
D. of , to learn
解析：
试题分析:强调句式， It is adj for sb to do sth，做某事对某人来说怎么样。本句中it是形式主语，指代后面不定式内容做形式主语，注意for后面接表示人的对象,to后面接动词,故选A。