Complex sentence: Over 10,000 bronze items of weaponry have been recovered from the pits; most of these arrowheads, there are also 279 arrows, 22 bronze swords, and smaller number of other weapons.
Split into simpler sentences: Over 10,000 bronze items of weaponry have been recovered from the pits, with most of these arrowheads. Of the rest, there are 279 arrows, 22 bronze swords, and smaller number of other weapons.