Complex sentence: On 22 March, the KAR companies attacked but withdrew to the south, when a planned Belgian assault failed to materialize but the Italians were surprised by the flanking manoeuvre and evacuated to Saïo.
Split into simpler sentences: On 22 March, the KAR companies attacked but withdrew to the south when a planned Belgian assault failed to materialize. Still, the Italians were surprised by the flanking manoeuvre and evacuated to Saïo.