问题补充：
It is because English is being widely used at present .
A. why we learn it hard
B. that we learn it hard
C. which we must learn
D. when we should learn
答案：
A. why we learn it hard
(答案→)B. that we learn it hard
C. which we must learn
D. when we should learn
解析：本题考查强调句型的用法。本句是对because English is being widely used at present的强调,在强调句型中常用It is/was...that...结构。
