用所给词的适当形式填空（5分）：

小题1:I have been in No. 2 Middle School for two years. I don’t worry about _______________

(not have) new good friends.

小题2:The big birthday cake _____________________ (divide) into ten parts tomorrow.

小题3:It is silly of you __________________ (not forgive) others for their faults.

小题4:I think he is __________________________ (suitable) person for the job of all.

小题5:My grandma is in a good mood because tomorrow will be her__________ birthday. (nine)

当两列变量均为二分变量时，应计算哪一种相关？（）

A.积差相关（两个连续型变量）

B.φ相关

C.点二列相关（一个是连续型变量，另一个是真正的二分名义变量）

D.二列相关（两个连续型变量，其中之一被人为地划分成二分变量。）