A little snail(蜗牛)felt tired from carrying his shell(壳) all day. He asked his mother, “Mum, why do we have to carry our shells?" His mother told him, “Because we don't have any bones in our body. We can only crawl(爬). The hard shell not only helps us move faster, but also protects us."
The little snail was still puzzled. “Caterpillars(蝴蝶的幼虫) don't have bones, either. They can't even crawl. But they don't need to carry heavy shells."
“How about earthworms(蚯蚓)? They don't have bones, they don't crawl fast and they don't turn into butterflies. And they needn't carry heavy shells. "The mother told him. “Earthworms live underground and the land protect them."
Hearing this, the little snail started to cry. The mother snail comforted(安慰) him. That's why we have shells! We don't depend(依靠) on the sky. We don't depend on land. We depend on ourselves."