— this math problem seemed quite simple to me but when I tried to work it out I just c

问题补充：

— , this math problem seemed quite simple to me, but when I tried to work it out, I just couldn’t.

— There are always things like this, I think.

A. On one hand

B. In my opinion

C. At first sight

D. On its own

答案：

A. On one hand

B. In my opinion

(答案→)C. At first sight

D. On its own

解析：短语辨析. A.一方面B.以我看来C.初看之下D.就其本身而言.句意:初看之下,这道数学题对我来说相当简单,但是当我尝试把它计算出来时……故选C，最符合语境。