甲：Mg（NO3）2、NO2、O2乙：MgO、NO2、O2 丙：Mg3N2、O2 丁：MgO、NO2、N2
如图是染色体、DNA和基因关系的示意图，请看图作答：
A. Today is Sunday.
B. He flies a kite.
C. The girl plays with her teddy bear.
D. We read books.
E. They play catch with a ball.
