Complex sentence: By March 1964, MalcolmX had grown disillusioned with the Nation of Islam and its leader Elijah Muhammad and said that he had many regrets about his time with them which he regarded as largely wasted.
Split into simpler sentences: By March 1964, MalcolmX had grown disillusioned with the Nation of Islam and its leader Elijah Muhammad. He said that he had many regrets about his time with them which he regarded as largely wasted.