there are so many problems remaining to be settled

问题补充：

there are so many problems remaining to be settled?REMAIN不是没有被动语态和进行时吗.记动词要不要记及物不及物.可不可以记意思,记词性容易忘实用性又很低

答案：

当然要记,不注意便不会用.

remaining to be settled 是现在分词短语作后置定语,修饰主语so many problems 的

可以改为定语从句：

there are so many problems 【which remain(系动词） to be settled?】

有许多问题有待解决