A:12,1
B:12,2+22
C:2−22,2+22
D:2−22,1
用任意一个平面截一个几何体,各个截面都是圆,则这个几何体一定是( )
—I think it's really necessary. It is reported that the food that Chinese people _____ every year is enough to feed 200 million people for a year.
某生物实习小组的同学用河水、水草、洗净的砂、草食小鱼、广口瓶、凡士林等材料制作的生态瓶如图。下列对此说法不正确的是( )
下列句子朗读停顿(“/”)标示出来。
①种豆南山下
②晨兴理荒秽