产业政策的( )是经济结构转换问题，特别是促进产业结构优化和升级问题。
A．目标B．实质C．对象D．核心
参考答案：D
30. Barack Obama told millions watching him that his grandmother’s influence on _______ he is and the way he views the world was significant.
A．how
B．who
C．where
D．which
交流测速发电机可分为永磁式和电磁式两种。
