is necessary us learn English well.
A. It, of, to
B. This, of, of
C. It, for, to
D. This, for, to
网友回答
A. It, of, to
B. This, of, of
(答案→)C. It, for, to
D. This, for, to
解析：考察固定句型 It is +adj+for/of sb to do sth 当adj是人的一种品格时用of。题目中necessary不是人的品格，故选C 句意：对我们来说学好英语是很有必要的。