Moviegoers know that many special effects are created by computers, they often don’ tknow is that these scenes still require a lot of work.
A.That
B.Whom
C.What
D.How
正确答案：C
【考情点拨】考查主语从句引导词【应试指导】句意：常看电影的人知道许多特效都是通过电脑制作出来的但他们往往不知道的是制作这些场景还需要投入大量的工作分析句子结构可知空格所在从句在整个句子中充当主语从句中缺少宾语且宾语指的是事而非人故选C
