sentences:  Five days later, she arrived off Okinawa and commenced a week of mine-sweeping operations to clear the approach to the beaches for landing ships and craft.Each night she retired to a relatively safe area far offshore.On 1 April, when the assault waves rolled ashore, "Swallow" shifted from minesweeping duties to antisubmarine patrols and, but for two runs to Kerama Retto for supplies, continued that duty until 22 April.