_____he worked out the problem puzzled everybody present.请问空格是填 whether 还是 how THX~

_____he worked out the problem puzzled everybody present.请问空格是填 whether 还是 how THX~
_____he worked out the problem puzzled everybody present.
请问空格是填 whether 还是 how
THX~

_____he worked out the problem puzzled everybody present.请问空格是填 whether 还是 how THX~
How
如果用whether,应该是Whether he could work out the problem