Simplify the following text for a Grade 13 native English-speaking person.
Original: Unless you explicitly specify otherwise , all contributions to Wikipedia are dual-licensed under the CC-BY-SA license and the GFDL ; therefore , if you elect not to adopt additional licenses , no action is necessary .
Simplified: Unless you specifically say otherwise , all contributions to Wikipedia are licensed under the GFDL ; therefore , if you elect not to adopt additional licenses , no action is necessary .