问题
选择题
____ has been proved again and again that ____ is said in the ads greatly affects people’s impression of the products.
A．There; what
B．There; that
C．It; which
D．It; what
答案
答案：D
考查名词性从句。句中it作形式主语，真正的主语为that what is said in the ads greatly affects people’s impression of the products；what在从句中作主语，故选D。