what is a complaint letter? ______
A. 慰问信
B. 推荐信
C. 投诉信
A complaint letter is used to complain about a______, service or a person to the higher authority.
A. product
B. produce
C. producting
The complaint letter should be concise, clear and ______.
A. fact
B. factual
C. facted
The letter has to clearly mention ______ actually the problem is.
A. what
B. when
C. why