see below
simple subject: workmen simple predicate: repaired
simple subject: class simple predicate: laughed
simple subject: day simple predicate: ended
simple subject: hours simple predicate: passed
Note: Simple subject is the noun/pronoun that the sentence is talking about. It does not include any of the adjectives modifying the subject.
Simple predicate is the specific action/verb that the subject did. Simple predicate may be a verb phrase (main verb with auxiliary verb). It does not include adverbs or other modifiers for the verb.