Most balloons expand as they rise, so that they stay at the same pressure as the outside air.
(Most balloons; expand; T:as they rise; so that they stay at the same pressure as the outside air) (they; rise; ) (they; stay; at the same pressure as the outside air)
Most balloons they they
expand rise stay
T:as they rise so that they stay at the same pressure as the outside air
at the same pressure as the outside air