问题
单项选择题
Because it is not a serious problem, we are not necessary to take strict measures against the student.()
A. we not need
B. not necessary for us
C. it being unnecessary
D. it is not necessary for us
答案
参考答案：D
解析：
本题考查结构应用。当动词不定式作主语时，常用it作为形式主语放在句首代替真正的主语，结构为it is+形容词(for sb．)to do sth．。所以，答案是D。