下列反应既属于氧化还原反应,又属于吸热反应的是[ ]
A.铝片和稀盐酸反应
B.Ba(OH)2·8H2O与NH4Cl的反应
C.灼热的碳与二氧化碳的反应
D.甲烷在氧气中的燃烧
答案:C
— Do you know our town at all?
— No, this is the first time I ______ here. [ ]
A. has come
B. come
C. had come
D. have come
常用熔断器主要有哪二种,做什么保护?