产业政策的( )是政府以实现特定的产业发展目标对经济活动的一种自觉干预，是对社会挺体利益的维护。
A．核心
B．目标
C．实质
D．内容
参考答案：C
_____with what they had done, we felt we still had too much to do.
A．compared
B．comparing
C．having compared
D．being compared
田间检验中前控和后控的主要作用有哪些？
