2 Girls Move

Two prostitutes moved to a new town, and on their first Sunday, went to church.
One of the girls was quite proud of her singing; the other felt she couldn't carry a tune in a bucket, so was quiet.
After one desultory hymn, the priest berated the congregation, "Quite clearly, there are some who are singing, and some who are not. Can we please have a more concerted effort for the other hymns?"
One whisper to her friend, "My word, how did he know about us so quickly?"