There is another problem need to be solve/solved?

题目

There is another problem need to be solve/solved?
不确定是用solved还是solve,为什么呢?

答案

There is another problem need to be solved?
当然是用“solved”
这个很容易判别,"to be + 过去分词" ----> 被动式
例如:There are lots of things need to be done.（尚有很多事情待办.)