— Hello. May I speak to David, please?

— ______. [ ]

A. I am David.

B. Who are you?

C. Speaking

D. Do you really want him?

将根尖各部分的名称和功能用直线连起来

根冠              A 吸收水分和无机盐的主要部分

分生区            B 细胞具有分裂能力

伸长区            C 保护分生区

成熟区            D 使细胞迅速伸长．