Complex sentence: During the US invasion of Afghanistan it was one of the last strongholds of the Taliban, and was suspected to be the hide-out of Al-Qaeda leader Osama bin Laden, and was the theatre in December 2001 for the Battle of Tora Bora.
Split into simpler sentences: During the US invasion of Afghanistan it was one of the last strongholds of the Taliban. As the suspected hide-out of Al-Qaeda leader Osama bin Laden, it was the theatre in December 2001 for the Battle of Tora Bora.