A:a+b,40
B:a,20
C:大于a,20
D:小于a,20
-----______ there any living things on other planets ?
-----I have no ideas. Maybe we can know more about that in the future.
2013年2月28日,全国科学技术名词审定委员会称PM2.5拟正式命名为“细颗粒物”,网友戏称“霾尘”.PM2.5是指大气中直径小于或等于0.0000025m的颗粒物.请将0.0000025用科学记数法表示为____
已知圆C: x+32+y2=100和点B(3,0),P是圆上一点,线段BP的垂直平分线交CP于M点,则M点的轨迹方程是( )
— _____ would you like, please?
—A hamburger.