I'm pretty sure we're gonna be late to the party does this contain slang

Yes, it contains slang.

Explanation:

The word 'gonna' is slang for going to. (informal contraction)

Hope this helps!!

~gloriouspurpose~

comfortable

explanation:

one type of the adjectives is predicate adjective. a predicate adjective is an adjective which follows a linking verb and modifies or refers back to the main subject of that linking verb.

it usually is used just before the noun it modies.

here in this example:

'penguins seem comfortable in the coolest habitats', comfortable is the predicate adjective which follows the linking verb 'seem' and modifies the noun.