Complex sentence: By 1975, Mandela had become a Class A prisoner, allowing greater numbers of visits and letters; he corresponded with anti-apartheid activists like Mangosuthu Buthelezi and Desmond Tutu.
Split into simpler sentences: By 1975, Mandela had become a Class A prisoner, allowing greater numbers of visits and letters. He corresponded with anti-apartheid activists like Mangosuthu Buthelezi and Desmond Tutu.