I think you should think twice .Once , the decision won’t be easily changed .
A. making
B. to be made
C. being made
D. made
网友回答
A. making
B. to be made
C. being made
(答案→)D. made
解析:句意为:我认为,你应该三思。一旦作出了,决定便不容易改变。once为表条件的用法,引导的部分做状语,其逻辑主语是the decision,与make之间的关系是被动, 故应为done.表被动的含义,所以答案应为D。