集约型经济增长方式是指主要依靠( )来实现经济增长。

A．增加自然资源投入

B．增加劳动力投入

C．提高生产要素的生产率

D．增加生产资料的投入

At the railway station, the mother waved goodbye to her daughter until the train was _______.

A．out of sight

B．out of reach

C．out of order

D．out of place