only to find

only to findI hurried home only to find her gone.=
I hurried home and found that she had gone.
Why ''her gone'' is used instead of ''she has gone'' ?- see the example above and you will understand the meaning.
What it means when using gone after her? gone is to modified that she has already gone or left or she is no longer there

There are an estimated 200-300 shops selling fake products on
a two-for-one exchange basis.
What does the word ''two-for-one'' mean?
Pay price of one unit and get two units.=buy one and get one free買一送一

And Why using ''an'' with ''200-300 shops'' ?
an estimated 200-300 shops= it is estimated is starting with an Vowel E.

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