no plural; as,
Your _3's_ are too much like your _5's_, your _a's_
like your _u's_.
Don't use so many _and's_.
Write sentences in each of which you use one of the following words
correctly:
you're we're who's they're
your were whose there
it's he's don't their
its his doesn't
Explain why the apostrophe is used in the following: