conditional verbs: "Should have gone", "would have given" etc

hopefully a quick question this time.

conditional verbs like "should have gone", "would have given".

Are they treated as 1 composite verb, or for example in each phrase is there in fact 3 verbs?

[mykwyner]

If you "treat" them as a single verb or three separate verbs with a single meaning, there is no difference as long as you use them (it) properly.

[sarah b]

You could divide them up as three seperate verbs; 'Should' is the modal verb, 'have' is the auxilary verb and 'gone' is the main verb. However, in the sentence 'Sarah should have gone' its perfectly okay to seperate the two sentence elements as; subject (Sarah) and predicate (should have gone), thus referring to all three verbs as one verb phrase.