Though having discussed it for long they still havent reached an agreement they should

问题补充：

Though having discussed it for long, they still haven reached an agreement they should pour more money into the project.

A. whether

B. if

C. that

D. what

答案：

(答案→)A. whether

B. if

C. that

D. what

解析：A句意：尽管讨论了很长时间，他们依然没有就是否应该把更多的钱投入到这个项目上达成一致意见。根据句意可知用whether引导该同位语从句，if不能引导同位语从句，故选A项。