Green sea turtles (海龟) are the world's largest species of hard-shelled seaturtle. While most individuals weigh about 136 to 181 kilograms, some can be __56__heavy as 204 kilograms. These turtles are found nesting (筑巢) along the coastlineof more than 80 countries, with the largest nesting populations __57__ in Costa Ricaand Australia. 

Green sea turtles spend most of their lives underwater, __58__ they can restfor up to five hours at a time before __59__ up for air. When active, they typically stayunderwater for a few minutes and swim up to the surface to __60__ air for a few seconds. Green sea turtles also bathe in the sun __61__ land. 

Unlike most other sea turtles, adult green sea turtles eat primarilyplant-based foods __62__ of seaweed and sea grass. Scientists believe these green foods__63__ the sea turtle's fat its green color. 

Similar to other sea turtles, green sea turtles travel long distances __64__their feeding grounds and their nesting sites, with recorded distances __65__ than 2,600kilometers. They have strong flippers (鳍形肢) that help them __66__ in the water. 

Female green sea turtles leave the water in __67__ to lay eggs on thebeach and will choose the same nesting __68__ as where they were born. A female willdig __69__ a nest with her flippers and lay about 115 eggs. Then she'll cover theeggs __70__ sand and return to the sea. After about two months, the babies will usea special "egg tooth" to break their shells and hatch (孵化) from their eggs. 

The first few years of a green sea turtle's life are spent __71__ at sea,where they feed on tiny animals and plants __72__ live in the surface layer of the sea.As they grow older, the turtles move to __73__ waters along the coast, where theyfind sea grass to eat.