1 . What a c__________! I wasn’t expecting to see you here.

2 . The timing of the two letters, with the first published before the release of the WHO report and the second after, was hardly a ________ (巧合). (根据汉语提示单词拼写）

3 . What a c_____________! We were born at the same hospital on the same day!

4 . Since you seem to be surprised at the fact that in China, three generations, grandparents, parents and children, often live together, it will be my pleasure to explain this _________ to you.

A．phenomenon

B．coincidence

C．example

D．detail