The long form of "It's rather……"

[Odessa Dawn]

It's rather late in the day to start studying - your exams are next week.
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Source: late in the day - definition in British English Dictionary & Thesaurus - Cambridge Dictionary Online
Will you tell me the long form of "It's" in the aforementioned sentence?
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[charliedeut]

Hi,

It's "It is".

charliedeut

 

[Cory Sampson]

"It's" is the contracted form of "It is".


EDIT: beaten.