he ___ research these three years,and he _several discoveries this year.a.has been doing ,made b.has been doing ,has made.能否说明原因？

分类: 作业答案 • 2022-02-17 12:19:45

问题描述：

he _____ research these three years,and he ___several discoveries this year.
a.has been doing ,made b.has been doing ,has made.
能否说明原因？

答

he _____ research these three years,and he ___several discoveries this year.a.has been doing ,made b.has been doing ,has made.能否说明原因？