问题补充：
---This physics problem is too difficult. Can you show me , Wang Lin?
--- Sure.
A. what to work it out
B. what to work out it
C. how to work it out
D. how to work out it
答案：
A. what to work it out
B. what to work out it
(答案→)C. how to work it out
D. how to work out it
解析：可联系答.案.网客服索取。
