I don ’t really know who she ________ with.A. hangs outB. hangs overC. hangs upD. hangs

“Do you know that girl with the long hair？” “I don’t think so, although she __________

I don’t know the origin of this custom.

I don’t know if the pain.ting is authentic

I don’t know the origin of this custom.

-- I really don know how to thank you enough.--______.A.No problemB.Think nothing of itC

There isn any difference between the two. I really don know _________.[ ]A. where to choose B. w