It is a good plan in theory, but it to be seen whether it works in practice.
A. keeps
B. stays
C. stands
D. remains
网友回答
A. keeps
B. stays
C. stands
(答案→)D. remains
解析：考查动词：A. keeps保持，B. stays停留，C. stands站立D. remains仍然，句意：这在理论上是个好计划，但是否能在实践中起作用还有待证实。选D。