After careful investigation we find that one of the statements t

After careful investigation we find that one of the statements to be untrue.
A、is turned out
B、have been turned out
C、has turned out
D、have turned out
【正确答案】：C
【题目解析】：one of the statements陈述之一，是单数，排除B、D项；强调过去动作对于现在的影响或者结果，C项现在完成时符合题意。