我国南北方气温相差接近50°C的季节是
A:春季
B:夏季
C:秋季
D:冬季
下图的宣传画与下列那一历史事件有关( )
鸟卵的下列结构中,将来可以发育成雏鸟的是( )
—I don't know which skirt was ______, so I took them both.—Yes, it's really difficult to choose.