The invention ______ she spent two years will do good to the world.

问题描述:

The invention ______ she spent two years will do good to the world.
A.whichB.thatC.on whichD.when
选什么啊?讲一讲,谢谢!

选择on which,spend some time on something,是词组
将on 提前,与which组合,做invention的定语
也可以是这样the invention which she spent two years on will do good to the world.