A:①③
B:②④
C:①④
D:②③
— Jack has made a decision.
— But I suggest that he should think it over so that he won't regret it later on.
—Let's________ parents.
位于海林市的林海雪原,是英雄杨子荣战斗过的地方,解放战争时期,著名的“智取威虎山”就发生在这里.在牡丹江通往威虎山的公路中,公路从山底到最高点的高度差约800米,一辆满载货物的卡车总质量为23吨,汽油机效率为25%,汽车爬坡的机械效率为80%,问卡车到达山顶需多少千克汽油?(汽油热值为4.6×107J/Kg,g=10N/kg)