life jacket
5.He tied up both ends of his shirt, blew it up as a life-jacket and drifted on the sea. Fortunately, a passing boat rescued him. 
6.Among the designs left by Leonardo da Vinci almost 500 years ago—with notes written backward to be read with a mirror—were the parachute，life jacket， water pump，swim fins，Well digger，paddle-wheel boat，horseless carriage ，sprocketchain， steam gun， water turbine，lens-grinding0 machine，shrapnel ，machine gun， airplane， helicopter，submarine，and mass production .
7.He tied up both ends of his shirt, blew it up as a life-jacket and drifted on the sea.Fortunately, a passing boat rescued him. When the boat reached Bangka, he was the first person to jump ashore. There, he knelt and made 108 kowtows to the sea, swearing that he would never set foot on a boat again.
