A：细胞壁与原生质层的伸缩性不同
B：液泡的有无
C：原生质层两侧的溶液具有浓度差
D：细胞核的多少
（2016•十堰）- I shouted to you at the gate, but you didn't hear me.
- Really? I ____ a telephone call to my mother.
