–– Beijing is a big city, isn't it?
–– Yes. In fact, it's one of ________ cities in the world.
A：big
B：bigger
C：biggest
D：the biggest
电影放映后，当走进电影院时，瞳孔是由小变大的．
—She's my sister.
多音字组词。
挑tiǎo____ tiāo____
折zhé____ shé____
2.64+0.8x=4.64
X=____
（用小数表示）
