In Constructions^x, Proper Grammar^x

See, this the weird thing. While that last sentence doesn't sound right, this one does:Are these the pens you're looking for? Thanks, but no, those aren't the ones I'm looking for.

If this sentence originated in the U.S., then failure to make the number (that is, the singularity or plurality) of the pronoun (in this case "their") match the number of the noun (in this case ''seller") is the result of what is termed "political correctness."...

It is true that "ones," according to proper grammar should not follow "these" or "those" only because one is a singular object. If there is a plural number, "one" becomes inappropriate however there are few people I know (I live in the midwest US) that do not use this construction, as in common...

for I and YOU pronouns...in rules of using is and are....singular nouns/pronouns normally follow the linking verb in singular form. However with I and YOU, even if they appear to be one person. I and YOU are exceptions. the proper grammar for it is: "I" ---> the present tense for "were" is am....