slug [slʌɡ] n. 鼻涕虫; 蛞蝓
snail [sneɪl] n. 蜗牛
shell [ʃel] n. 壳; 外壳
Slugs and snails feed at night.
The snail is pushing out its horns.
Most snails have shells on their backs.
My daughter screamed when she saw a slug.
Turtle pulled her head and feet inside her shell.