[zoneoni]

There is a definitive way to use it's and it has.


it's is a possessive adjective, it implies that the implicit subject or an aforementioned subject in a previous sentence has properties that are being described in the coming predicate pertaining to the possessive meaning

Example 1 :
As the clock rang 12:50,
Marlene told me it was time to go.
But it's telling me otherwise.

So because the clock rang 12, Marlene was telling me it was time to go. But it's, referring to the clock was giving him a different impression. It relies on the assumption that the time to go was not 12:50 and the clock was what was being inferred to by the it's.

Example 2:
It's time to go.

It's referring to a relative time, in this case the present.

Usually using It's and it has is considered informal and sometimes you can't really replace them.


It has is usually a definitive connotation and has no use for implicitly.

Example 1:
It has colored fangs.

Definitive statement and not really all that implicit except for the sentence that it is directing itself from.

Example 2: Why is it, that it has wings?

The first it is the deriving form while the second one is the definitive form.
The first it is assuming that a previous sentence has already defined the reference.