Complex sentence: An escape trunk is a small compartment on a submarine which provides a means for crew to escape from a downed submarine; it operates on a principle similar to an airlock, in that it allows the transfer of persons or objects between two areas of different pressure.
Split into simpler sentences: An escape trunk is a small compartment on a submarine that provides a means for people to escape from a downed submarine. It operates on a principle similar to an airlock, in that it allows the transfer of persons or objects between two areas of different pressure.