I would appreciate very much if you could change the plan a bit to make it more workable.

网友回答

A. that
B. this
(答案→)C. it
D. you
解析：考查it用法。本题中的it是一个特殊用法，表示无所指it；如make it, get it；如I hate it when it is hot。我讨厌天气热。句意：如果你能改变一下计划让它更为实用，我会非常高兴。故C正确。