Once upon a time..

[vader jr]

I have a question.

"Once upon a time, there was a boy and a girl..."

or

"Once upon a time, there were a boy and a girl..."

Thanks.

 

[emsr2d2]

I have a question.

"Once upon a time, there was a boy and a girl..."

or

"Once upon a time, there were a boy and a girl..."

Thanks.

Was. What you're actually saying is "Once upon a time, there was a boy and there was a girl......"
It would be "Once upon a time, there were two children......"

 

[tedtmc]

there were a boy and a girl

Another test is - it does not sound right/natural, does it?