I received a number of , but of them is valuable to me.
A. advice; both
B. advice; all
C. suggestions; both
D. suggestions; none
网友回答
A. advice; both
B. advice; all
C. suggestions; both
(答案→)D. suggestions; none
解析：根据语境可知此句的含义是我收到许多的建议，但没有一个是有价值的。a number of表示许多，大量的意思，其后常跟名词的复数形式；none of其后常跟名词的复数形式表示没有一个的意思，其做主语时谓语动词要用单数形式。由选择项的提示可知选择D。