厂商在生产规模扩大时由于自身原因所引起的产量增加和成本降低是指()。
A.内在经济
B.外在经济
C.内在不经济
D.外在不经济
参考答案:A
He used to ______ late. But now he is used to______ early. [ ]
A.sleep, get up
B.sleep, getting up
C.sleeping, get up
D.sleeping, getting up
曲柄连杆机构的组成?