1989年出版的《商情摘要》综合类指数中同步指标综合指数包含的同步指标数有( )
A．11种B．4种C．7种D．10种
参考答案：B
After living with his grandparents in the countryside fort en years, the boy returned to
The big city____his parents worked.
A．which
B．where
C．that
D．when
