题目

下列不属于成熟植物细胞发生质壁分离原因的是 A．外界溶液浓度大于细胞液浓度  B．细胞壁和原生质层的伸缩性不同 C．细胞壁和原生质层都有选择透过性   D．水分子从低浓度向高浓度一侧扩散 答案：C--- I rang you at about ten, but there was no reply. --- Oh, that was probably _____ I was seeing the doctor.A．forB．whyC．whenD．how