Complex sentence: Two platoons of'C' Company rushed up from the south to join'A' Company and at 15:00 started forward and by 16:50 had moved past the scattered Japanese opposition to reach the south arm of the Bitoi River.
Split into simpler sentences: Two platoons of'C' Company rushed up from the south to join'A' Company and at 15:00 began their advance. By 16:50 they had moved past the scattered Japanese opposition to reach the southern reaches of the Bitoi River.