Original sentence: Bactria proper was north of the Hindu Kush mountain range and south of the Amu Darya river, covering the flat region that straddles modern-day Afghanistan, Tajikistan, Pakistan and Uzbekistan
Edited sentence: Bactria proper was north of the Hindu Kush mountain range and south of the Amu Darya river, covering the flat region that straddles mainly in modern-day Afghanistan, but also includes small parts of Tajikistan, Pakistan and Uzbekistan