在已受精的鸟卵中,可以发育成雏鸟的结构是( )
A:系带
B:胚盘
C:卵黄
D:卵白
下列关于葡萄糖的叙述,错误的是 ( )
— Where is Mr. Green, do you know? I have something to tell him.
— He to Hong Kong for a meeting. He home three days ago.
如图,△ABC中,∠ACB=90°,沿CD折叠△CBD,使点B恰好落在AC边上的点E处.若∠A=22°,则∠BDC等于( )