pontoon

/pɒn'tuːn/　/pɑːn'tuːn/　noun

★ a temporary floating platform built across several boats or hollow structures, especially one used for tying boats to

★ a boat or hollow structure that is one of several used to support a floating platform or bridge

・ a pontoon bridge

across　p)～を横切って、～のいたるところに

hollow  /'hɒləƱ/　/'hɑːləƱ/　adj)木･壁･管などが中空の

★ having a hole or empty space inside

・ a hollow ball/centre/tube/tree

・ a hollow metal cylinder

・ The tree trunk was hollow inside

・ Her stomach felt hollow with fear