He could not contrive an explanation for his misbehavior.
The criminal contrived a plan to escape from jail.
Early humans contrived practical tools out of simple stone.They contrived how to get past the guards unnoticed.
When it has a subject, verb, punctuation, capitalization, a predicate, and a complete thought. A sentence is a sentence when it is handed down by a judge (or a magistrate).
Since he could not pass the exam, he contrived an excuse to leave the class.