化学反应中的能量变化主要表现为热量的变化。下列反应属于吸热反应的是[ ]
A.木炭燃烧
B.酸碱中和
C.酒精燃烧
D.CaCO3加热分解
答案:D
His mother wants him ________at home all day.
Really? That’s terrible.
A.stays
B.stayed
C.to stay
D.staying
边角煤、采区内残留煤柱、孤岛工作面等高应力集中区开采前,必须首先进行()评估。