Problem with conditional type 2 and 3

[Waldorf]

what is the difference between could, might,should which can replace would in type 2 and 3.
I only know would can be replaced with these words but i can find when I should use
would
could
should
might

I cant see the difference
thanx for any help

[CID]

schau vielleicht schon mal hier:

http://www.englisch-hilfen.de/grammar/if.htm

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