Complex sentence: The US Navy requirement was originally announced in 2008, as a required replacement for the F/A- 18E/F-which at the time appeared to be focused on strike roles, with a mix of manned and unmanned options on the table.
Split into simpler sentences: The US Navy requirement was originally announced in 2008, as a required replacement for the F/A- 18E/F. At the time, the requirement appeared to be focused on strike roles, with a mix of manned and unmanned options on the table.