People know little about what the long-term effect of the A(H1N1) flu vacci
问题描述：
People know little about what the long-term effect of the A(H1N1) flu vacci
People know little about _______the long-term effort of the A(H1N1) flu vaccine will be.A what Bwhich Cwhom Dthat
答
人们对于H1N1流感病毒的接种疫苗的长期影响了解甚少.请问选项是什么？why?A这里不是定语从句，不选Bwhich和 Cwhom，这是what结构的作know about 的宾语。that没有这种用法