original: He returns in the 2007 series of Doctor Who, reuniting with the tenth incarnation of the Doctor, and returned again for the 2008 series.
simplifications: He returns in the 2007 series of Doctor Who, reuniting with the tenth version of the Doctor.  He comes back again for the 2008 series. He returns to Doctor Who in 2007, reuniting with the tenth Doctor. He returned again in 2008. He returns in the 2007 series of Doctor Who, joining the tenth incarnation of the Doctor. He will return again in 2008. He returns in the 2007 series of Doctor Who. At that time, he reunites with the tenth incarnation of the Doctor. He returned again for the 2008 series. He came back in the 2007 Doctor Who series, joining the tenth show of the Doctor. He came back again for the 2008 series. In the 2007 series of Doctor Who, he returns, reuniting with the tenth incarnation of the Doctor, and again for the 2008 series. He comes back in 2007 to meet the Tenth Doctor again. He also appears in the 2008 series. Returning in the 2007 and 2008 Doctor Who series, he is the tenth version of the Doctor. In 2007 and 2008 he returned to the Doctor Who series. In 2007, he reunited with the Doctor's tenth incarnation. He returned to the 2007 Doctor Who series, reuniting with the tenth origin story of the Doctor, and returned to the 2008 series.