Pay attention to who's (who is) and it's (it is) when used as possessive pronouns, and the use of whose:
WHOSE = WHO OWNS / WHO DOES THIS BELONG TO?
1. Whose briefcase is this?
Note: you can't use who's in this example, because it would sound like "Who is briefcase is this?"
2. Do you remember whose turn it is to walk the dog?
3. Who's [who is] going to put these shoes away??! Whose turn is it to tidy up this week?#!!
WHO'S = WHO IS -or- WHO WAS
1. The guy who's [who is] buying the house is here.
* Note: you can't use whose in this case, because you want to say "who is", so use who's
2. I know it's [it is] you who's going to do the shopping this week - it's written up here on the notice board ... but whose turn is it next week?
*****
I know you're probably thinking this is a pain to learn, but really, when it comes to grammar, punctuation, spelling and apostrophes, you need to be able to know when and where to use the different parts of speech. Whether you're [you are] working or at home, your workmates or family will turn to you for help when they have trouble writing letters and reports. You'll become known as the "smart" one in your team, and you can feel a great sense of satisfaction.
You may not know the answer to all their grammatical questions, but you can certainly find out quickly enough! Remember ...Who's = Who is ...? | Who was ...? | Who has ... ?
Whose = Who owns ...?
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