玉米根尖分生区细胞会不停地分裂生长。此时这些细胞[ ]

A．两组中心粒会分别移向两极

B．有K⁺穿过原生质层进入大液泡

C．染色体数目不断减少

D．保持着全能性

— Mary was heard            just now. What happened?

— John was telling a joke.[ ]

A．cry

B．to cry

C．laugh

D．to laugh