Answer:
1. lentamente.
2. atentamente.
3. parada frecuentemente.
Explanation:
To form an adverb from an adjective, it becomes feminine and the suffix is added –mente:
alegr-e -> alegr-e-mente
Adverbs normally depend on the verb and serve to indicate how the action expressed by the verb develops:
Ana lleva una vida estupenda -> Ana vive estupendamente