问题补充：
I think physics is and difficult .
A. confused; to learn
B. confusing; to be learned
C. confused; to learn it
D. confusing; to learn
答案：
A. confused; to learn
B. confusing; to be learned
C. confused; to learn it
(答案→)D. confusing; to learn
解析：可联系答.案.网客服索取。
