Our skin（皮肤） is like a bag that we live in． Inside the bag， （1） 　　． Our water is like the water in the sea． It is very salty． Also， like the ocean， we can lose our water． The sun could take it away． Our bag of skin keeps our body's ocean from drying up．

Our skin keeps out sunshine． （2） 　　Skin also keeps out dirty things． That's important because some kinds of them can make us sick． （3） 　　． It feels warm things， cold things， things it touches， and things that hurt it． A fire feels warm． A snowball feels cold．

Our hair helps keep things out of our eyes， ears， and nose． Hair is also good for keeping us warm． When we get too cold， our body hairs stand up and hold air close to our skin like a heavy quilt．    （4） 　　． Some animals have more hair than others， so they are not afraid of cold weather．

Our nails（指甲） are another special skin which are very hard． （5） 　　 ． Our nails aren't as strong or sharp as the nails that animals have． But they are just good for the basic human needs．

A．Our skin feels things B．Fingers are easily hurt C．our bodies are mostly water D．Hair keeps animals warm， too E．Too much sunshine can hurt us F．Hair can be used to make some quilts G．They help keep our fingers from getting hurt