A dinosaur is than a dog.
A:big
B:bigger
C:biggest
(2015·四川)设四边形ABCD为平行四边形,,.若点M,N满足,,则( )
燃烧是人类最早利用的化学反应之一.
(1)可燃物燃烧除需氧气外,还需满足什么条件?
(2)可燃物燃烧的剧烈程度与氧气浓度或接触面积等因素有关,任举一例加以说明.