Student or Learner
I don't know that we all need to work on the project together.
In most cases "I don't know" means "I have no idea," but this "I don't know that" means "I really don't agree that...," doesn't it?
Does "I don't know that ..." mean "I don't believe (that) ..." or "I doubt (that) ..."?
"I bet you've heard of me." "Well, I don't know that I ever have."
It can also be a polite way of saying that you don't want to work on the project as a team. "Is it really necessary that we do it as a team?"
You can also use "I don't know that what you're saying is completely right" as a polite way of saying, "I know that you have no idea of what you are talking about".
Mary said, "He wants to go with us, but I don't know that that's a good idea."
1. Does this sentence sound good?
2. Mary is not sure whether or not it's a good idea that he accompanies her, isn't she?