What is the antonym of briefly?

The antonym of "briefly" depends on the context. Here are some possibilities:

For duration:

* Extensively

* Thoroughly

* Lengthily

* At length

* In detail

For conciseness:

* Verbosely

* Prolixly

* Wordily

* Ramblingly

For fleetingly:

* Permanently

* Enduringly

* Lastingly

* Constantly

The best antonym will depend on the specific meaning of "briefly" in the sentence.