511>500.
答:一周能完成任务.
一曲蒙古族歌谣《吉祥三宝》优美动听。我国历史上由蒙古族建立的统一王朝是( )
—How many ________ are there on the table?
—Three. Are you thirsty? Let's cut one and eat it.
计算12a5b6c4÷(﹣3a2b3c)÷(2a3b3c3),其结果是( )