Complex sentence: Arsenal endured two comparatively poor seasons in 2005--06 and 2006--07, finishing fourth in the Premier League on both occasions and outside of the top two for the first time under Wenger's tenure.
Split into simpler sentences: Arsenal endured two comparatively poor seasons in 2005--06 and 2006--07. The team finished fourth in the Premier League on both occasions and outside of the top two for the first time under Wenger's tenure.