A:1
B:1/9
C:1/4
D:1/16
右图表示北半球某地太阳高度角的日变化状况,读图完成小题。
— Who is singing in the next room?
— It be Lucy. She likes singing at this time.
如图是四种粒子的结构示意图,对它们的描述正确的是( )