英语高手帮忙分析一句话

题目

英语高手帮忙分析一句话
A great deal of time was wasted playing but ought to have been fully used.
句子成份?这里but是什么用法?

答案

A great deal of time主语
was wasted谓语
playing（状语）（相当于in playing)
but并列连词
ought to have been fully used并列谓语,（与was wasted并列）
大量的时间被浪费用于玩耍了但本应该充分利用的.