问题补充：
There is a police car in front of the house of our neighbours. do you think ？
A. What；has happened
B. What；of happening
C. What；of being happened
D. Whatever；of happening
答案：
(答案→)A. What；has happened
B. What；of happening
C. What；of being happened
D. Whatever；of happening
解析：do you think可理解为插入语.
