—Mary was being badly treated when John happened to pass by and helped her out.

—I think it was not a pure ________ but had been well planned. [ ]

A. coincidence 

B. occurrence

C. arrangement  

D. incident

输卵管结扎术最适宜的时间为

A．月经干净后14天内

B．正常产后56天

C．难产后72天

D．人工流产后35天

E．月经干净后3～7天