题目分析：
本题的意思是：1998见证了很多冒险者推广线上课程，但是包括教员在内的很多人都开始质疑电脑屏幕是否足以替代教室。

选项分析：

A选项：平行触发语both…and…连接的两者不平行，需改为at both college and graduate level或both at college and at graduate level。

B选项：平行触发语both…and…结构不平行错误同(A)。另外，but连接的两个小句在实质上不能形成转折关系。But身后的小句的主干是it was also a year，a year身后的定语是for a large number of faculty who began questioning whether the computer screen was an adequate replacement for the classroom。该定语的核心词是a large number of faculty（很多教员），这个定语的核心词有误。要想和new ventures were promoting online distance learning（很多冒险者推广线上课程）形成转折关系，a year的定语必须是“开始质疑”，即，1998是一个开始质疑的年份，而不能说，1998是一个教员的年份。

C选项：平行触发语both…and…连接的两者不平行。

D选项：Correct. 本选项在语法和逻辑上均是正确的。

E选项：平行触发语both…and…连接的两者不平行。不定式的复合结构for faculty members to begin in large numbers questioning whether the computer screen was an adequate replacement for the classroom应改为普通的定语从句 when a large number of faculty members began questioning whether the computer screen was an adequate replacement for the classroom。这点考查了不定式和从句的区别，用之于本题，主句it was also a year发生后，不会改变begin这个动作的发生与否。

展开显示