Mr. Aubrière, 40, recounted his daring midnight escape in an interview Wednesday afternoon at a dilapidated African Union military base in Mogadishu, where he was awaiting a flight back to Paris.

If you want to use the same semantic element to contain both base enumerations and extended enumerations, consider solution 3 (union with a pattern).

But now European Union plans for a common tax base have begun to gain pace and may even take wing, in spite of several countries' efforts to stop them.