Gerry
Once upon a time [long, long, ago] you could force Google search to include a specific term, by including the + symbol
… and force it to exclude a specific term, by including the – symbol
All quite logical
But then they invented Google plus [whatever that is] and decided to kill the + functionality “to avoid confusion”
The use of quotation marks works [after a fashion] but is not as powerful as + was
Thankfully – does still seem to work, so you should be able to exclude the word single from your search results.
Hope that makes sense … give it a try !
MichaelG.