为改善生态环境，避免水土流失，某村积极植树造林，原计划每天植树60 棵，实际每天植树80 棵，结果比预计时间提前4 天完成植树任务，则计划植树__________ 棵．

---I was trying to carry out the plan, but I failed.

---Well, you _________, for we were uncertain it would do ________.

A．needn’t do that, in fact

B．needn’t have done, in effect

C．needn’t have, in practice

D．needn’t, in time