first and second conditionals

[galdina]

HI
Sorry because i don't know to speak fluently english because I am albanian.
My question is :how I can understand if the sentence is first.c. or second.c.
Here I have some examples .if you can answer in them please:
1.I(buy)that hat if it were not so dear.
2.If he wants to play the violin,I(play)the piano.
3.The dog (bite)you if it had not been tired up.
4.The child (be killed) if train hadnt stopped quickly.
Please answer in them and tell me summery about that answer.
Bye...........<3

[SirGod]

*Not a teacher

1.I would buy that hat if it were not so dear. (Conditional 2)

2.If he wants to play the violin, I will play the piano. (Conditional 1)

3.The dog would have bitten you if it had not been tired up. (Conditional 3)

4.The child would have been killed if the train hadn't stopped quickly. (Conditional 3)

[galdina]

Thank you very much