蓝鲸的英语写法如下：

Blue Whale

the world's largest animal

The body was blue-gray

They can grow up to 100 feet long

Blue whales are mammals

They live in the sea and eat small fish and other sea life

Some kinds of whales are in danger because humans catch them

这些句子和段落提供了关于蓝鲸的基本信息，包括它们的大小、颜色、生活环境和食性。希望这些信息对你有所帮助。