Thank you for your answer Toritatsu san. I wonder, did you forget to write 'not'?
You can say 'oh, they are not here yet.' - But without 'not' your answer is not correct!
Here are some other ways;
Nobody is here yet.
Nobody else is here yet.
Nobody else has arrived yet.
There is nobody else here yet.
Nobody else has come yet.
We are the only ones here.
We are the first ones to arrive.
We are the first ones here.
A common mistake:
Many students answer 'Nobody comes'. - This is NOT CORRECT!
'Nobody comes' is a repeat image, but this is a one time event.
You can say 'Nobody has come' - But the answers I gave first are better!
Are they here yet? (This is OK because it is a question - but 'oh' is not useful.)
Oh, they are not here yet! (This is OK as a statement.)
Oh, they are not here yet? (This is OK as a question.)
BUT;
'yet' is similar to Japanese まで - So imagine saying までいます' - It has the wrong meaning...