1> my pencil

Is this your pencil?
Is this your pencil ？
No, It’s not my pencil.
No, it’s not mine.

• Adjective possessive pronoun + Noun = Nominal possessive pronoun ;

2> be different from

Your school is very different from our school.
Your school is very different from ours.
Your school is very different from ours .

• differ【v.】->different【adj.】-> difference【n.】

Your school is very similar to our school.
Your school is very similar to ours.
Your school is very similar to ours .

• A be the same as B equally ;
• A be similar to B similar ;
• A be different form B Different ;

3> a friend of mine

I met a friend of mine at the station.
I met a friend of mine at the station .

• my a friend (X)
  You can't put ： Adjective possessive pronoun , Article , Demonstrative pronouns , Indefinite pronouns ;
  none of our passengers;

• at the station, Meet at a fixed point , So use at;

4> Dual possessive ( Noun + of + Nominal possessive pronoun )

• You can't put ： Adjective possessive pronoun , Article , Demonstrative pronouns , Indefinite pronouns ;

4.1> some friends of Curry’s

some friends of Curry’s
Curry Some of my friends

• Come to the point ;
• Adjective and nominal possessive pronouns of names , Homomorphism Curry’s;

4.2> these cute dogs of theirs

these cute dogs of theirs
Their cute little dogs .

• theirs = their daogs;