zhì / liú / jì / de / hǎi / yáng / zhōng / yǐ / jīng / chū / xiàn / le / xǔ / duō / zhǒng / lèi / de / shēng / wù志留纪的海洋中已经出现了许多种类的生物。Many kinds of organisms had already appeared in the oceans during the Silurian.