以下语句的逻辑翻译是什么?
"None of my friends are perfect." 
(A) A
(B) B
(C) C
(D) D答案： (D)
解释： 
F(x) ==> x is my friend
P(x) ==> x is perfect
D is the correct answer.
A. There exist some friends which are not perfect
B. There are some people who are not my friend and are perfect
C. There exist some people who are not my friend and are not perfect.
D. There doesn't exist any person who is my friend and perfect 这个问题的测验