The manager the workers how to improve the program since 9 a.m.
A. has told
B. is telling
C. has been telling
D. will have told
网友回答
A. has told
B. is telling
(答案→)C. has been telling
D. will have told
解析:句意为:从上午九点开始,经理在一直不停地告诫工人如何去完善这个项目。由时间状语since 9 a.m.可以先排除B和D;根据句意,此处需要的是“一直不停地告诫”,强调持续性,故完成进行时更好,所以答案选C。