Complex sentence: With the partition of India in 1947, Assam became a constituent state of India, But the district of Sylhet of Assam (excluding the Karimganj subdivision) was given up to East Pakistan (which later became Bangladesh).
Split into simpler sentences: With the partition of India in 1947, Assam became a constituent state of India. The district of Sylhet of Assam (excluding the Karimganj subdivision) was given up to East Pakistan (which later became Bangladesh).