Complex sentence: In order to quickly take the bridge, a jeep-mounted unit had been dropped as part of 1st Airborne, but most of this unit's jeeps were lost when 38 gliders failed to arrive on the drop zone.
Split into simpler sentences: In order to quickly take the bridge, a jeep-mounted unit had been sent as part of 1st Airborne. However, most of this unit's jeeps were lost when 38 gliders failed to arrive on the drop zone.