Poll: I can't find her- she ____ have left.
- Votes: 494
- Comments: 3
- Added: March 2008
- Polls: 1,169
- Votes: 688,589
- Comments: 4,851
"I can't find her - she must have left" is a just like a statement. "she must have left" is a confirmation from speaker.
This is a situation where MUST is being used to express certainty or supposition.
the use of MUST is grammatically suitable 2 fill in d gap above