He spent all his energies _________ a research _________ the causes of cancer.A.in,of Bin,on C.on,of D.on,into最后为什么用Into
2022-11-16 23:20:23 14次 反馈错误 加入收藏 正确率 : 100%
题目内容：
He spent all his energies _________ a research _________ the causes of cancer.
A.in,of Bin,on C.on,of D.on,into
最后为什么用Into
本题链接：
