可是我不知道怎么说啊

可是我不知道
But I did not know

可是我不知道怎么说啊
But I did not know how to said

But I don't know how to say .

But I don't know.
这样就行了。不用did not，因为时态不定。不可用过去式

都错了

but i don't know how to express