en diferentes ocasiones

= at different times, at various times

Ex. At different times Ms. Hinton has used revision, redraft, rewrite, new edition, revised edition, and second edition.

Ex. At various times the library holds computer classes for children and adults.

* * *

= at different times, at various times

Ex: At different times Ms. Hinton has used revision, redraft, rewrite, new edition, revised edition, and second edition.

Ex: At various times the library holds computer classes for children and adults.