Which word in the sentence is the predicate adjective? emerging from the bus station, the man looked lost.
a. bus
b. lost
c. station
d. looked

In the sentence: ‘Emerging from the bus station, the man looked lost.’ The predicate adjective is letter B: lost. The subject here is ‘the man’.    

A sentence basically has a subject, the object of the sentence or doer of the action and predicate, the verb, the adjective, etc. An adjective describes and modifies the noun. It could be used as attributive or predicative. Attributive adjective is included in the in the noun phrase it modifies while predicative adjective is not included in the noun phrase it modifies. Subject complements are any noun, adjective, pronoun that proceeds after a linking or helping verb (am, is, are, was, were, has been, are being, might have been, etc.], be, become, and seem. They are also called true linking verbs.