The same question is posted on Stack Exchange English Language Learners and I have not heard back from anyone yet.
Is the following sentence grammatically correct?
How would I know what things you think are not going well if you do not say anything?
The context is that someone said that things are not going well.
The other sentence posed to ask the similar question to ask about those things which are not going well is the following:
How would I know the things which/that you think are not going well if you do not say anything?
Another formation can be done by the removal of what before things and the insertion/replacement of those before things, as showed in the following sentence:
How would I know those things which/that you think are not going well if you do not say anything?