下列变化中,一定发生化学变化的是( )
A:汽油挥发
B:酒精燃烧
C:水结冰
D:矿石粉碎
有些植物到了秋冬季节就要落叶,这主要是为了( )
桃肉、西瓜子、葵花子分别是由下列哪项发育而来的()
–What did you do last Sunday?–I ________ to see the movie Tai Jiong with my friend. It was really funny.