A:π6
B:π3
C:π6或 5π6
D:π3或 2π3
There is some milk in the glass. (改为一般疑问句)
____ there ____ milk in the glass ?
不是每一朵花都能结出果实,能结出果实的花一定( )
①长有雌蕊和雄蕊 ②长有雌蕊 ③经历了自花传粉 ④经历了传粉 ⑤经历了受精.