Simplify the following text for a Grade 9 native English-speaking person.
Original: From February to April 2004 , Donaldson completed the SAS selection course , and was posted to I Troop , 3 Special Air Service Squadron in May 2004 .
Simplified: From February to April 2004 Donaldson did the Special Air Service training course , and was posted to I Troop , 3 Special Air Service Squadron in May 2004 .