We have ______ our techniques considerably since the work began1._英语解答

We have ______ our techniques considerably since the work began
1.refined
2.confined
3.defined
4.redefined

人气：283 ℃　时间：2020-01-30 02:15:43

解答

选1.refined
refine:改进
confine:限制
define:下定义
redefine:重新下定义