It couldn’t have been Mary that you heard shouting last night, as she is vacationing in Vermont at the moment.

A I think Mary is on holiday in Vermont now, so you may be wrong in thinking that you heard her yelling last night.

B Right now, Mary is having a holiday in Vermont, so it is impossible that it was she whose shouting you heard last night.

C Are you sure it was Mary who shouted to you last night, because, as far as I know, she is on vacation in Vermont at the moment?

D If it was Mary that you heard yelling last night, then she can’t be taking a vacation in Vermont at the moment.