用英语介绍大象的三句话可参考以下内容：

基本特征

"Elephants are the largest land animals on Earth, with long trunks and powerful legs. They are herbivores, primarily feeding on plants and using their trunks for breathing, smelling, drinking, and manipulating objects"。

社会行为

"These animals live in complex family structures, often consisting of females and their offspring. They are highly intelligent, capable of remembering events and emotions for extended periods, and exhibit strong social bonds"。

现状与保护

"Despite their gentle nature, elephants face threats from habitat loss and poaching for ivory. Conservation efforts are crucial to ensure their survival, as they play vital roles in ecosystems, such as seed dispersal and landscape shaping"。

总结：

大象以体型巨大、社会结构复杂和生态价值显著著称，但需加强保护以应对生存危机。