Much ______ been said about the problem but nothing ______ been

Much ______ been said about the problem but nothing ______ been done so far.
A、has, had
B、has, has
C、had, had
D、have, have
【正确答案】：B
【题目解析】：关于这个问题已经讲了许多，但是到目前为止却毫无进展。much与nothing均为不可数名词，故选B。