Copulative verb: A giant equal sign. They express states of being — what is, will be, or was. (seemed, appears, remains, stays)
Sensory verbs are copulative only if they act as an equal sign. E.g., “Ralph’s skin feels scratchy.” Feels is copulative. (feels, smells, looks, tastes)
Copulative verbs connect the predicate nominative and the predicate adjective.
Copulative verbs:
TO BE (am, are, is was, were, will be, shall be, has been, have been, had been, could be, should be, would be, might have been , could have ben, should have been, shall have been, will have been, must have been, must be.
SENSORY (look, sound, taste, smell, feel)
Words that express shades of meaning in reference to a state of being (appear, seem, grow, remain, stay)