Complex sentence: Polytechnics in Singapore provide 3-year diploma courses and, they accept students based on their GCE "O" level, GCE "A" level or Institute of Technical Education (ITE) results.
Split into simpler sentences: Polytechnics in Singapore provide 3-year diploma courses. They accept students based on their GCE "O" level, GCE "A" level or Institute of Technical Education (ITE) results.