We spend around one third of our lives in bed, and the body does a lot of its repair work as we sleep, so sufficient good quality sleep is very important to our health. It doesn't stop there,though-- some sleep positions are healthier than others. So which sleep position is the healthiest?

Sleeping on your back is the healthiest sleep position. Health benefits include avoiding back and neck pain. Because the head is raised above the stomach when you sleep on your back, this position is best for people who suffer from nighttime acid reflux (胃酸逆流) as well. Around 80% of heartburn (胃灼热) sufferers have problems during the night, so sleeping on their back could help a lot of people to enjoy a good night's sleep. If the sleep position alone is not enough to alleviate the condition, try raising the head of the bed by up to 4 inches by placing blocks under it.

When you sleep on your back, your face is in a natural position. This means less wrinkles（皱纹）. If you really can't face sleeping on your back, another healthy sleep position is the side sleep. It's almost as good as the back position, and it's better for people who snore(打鼾) and their partners. Whichever sleep position you choose, use a pillow that supports the head and the neck without raising the head unnaturally, as this can bring neck pain.

Maybe your mom or dad has told you, “Turn that down before you go deaf!” Well, they have a point.

【小题1】 You also could have tinnitus (耳鸣), which is a medical term for ringing in the ears. Your ears can feel “full” too. Although your hearing often returns to normal, the dangerous part is that you can lose it permanently if you listen to loud noise or music over and over again.

If someone is exposed to loud noise over a long period of time, permanent hearing loss can occur. 【小题2】 That’s why construction workers and factory workers need to wear ear protection.

【小题3】 Some famous musicians have suffered hearing loss and developed tinnitus — a real problem for someone who needs to hear to make and enjoy music. That’s why now you might notice that some of your favorite musicians wear hearing protection while they’re playing.

You too can help keep your hearing in good shape. Save your ears by wearing ear protection when you’re using machinery. 【小题4】 You also might want to give your ears a rest once in a while if you like wearing headphones. 【小题5】

If you're like most kids, you've probably heard at least one parent say, "Don't forget to take your vitamin(维他命)!" or "Eat your salad — it's packed with vitamins!" But what exactly are vitamins?

Vitamins and minerals are substances that are found in foods we eat. Your body needs them to work properly, so you grow and develop just like you should. When it comes to vitamins, each one has a special role to play. For example:Vitamin D in milk and fish helps your bones. Vitamin A in orange fruits and vegetables,liver and milk helps you see at night. Vitamin C in oranges and some green vegetables helps your body heal if you get a cut. Vitamin E in nuts, seeds, whole grains and green, leafy vegetables protects your lungs from becoming damaged by polluted air. B vitamins in green leafy vegetables help your body make energy from food.

When you eat foods that contain fat-soluble(脂溶性的) vitamins, the vitamins are stored in the fat tissues in your body and in your liver. They wait around in your body fat until your body needs them.

Fat-soluble vitamins are happy to stay stored in your body for a while — some stay for a few days, some for up to 6 months! Then, when it's time for them to be used, special carriers in your body take them to where they're needed. Vitamins A, D, E, and K are all fat-soluble vitamins.

Water-soluble vitamins are different. When you eat foods that have water-soluble vitamins, the vitamins don't get stored as much in your body. Instead, they travel through your bloodstream. Whatever your body doesn't use comes out of your body. So these kinds of vitamins need to be replaced often because they don't stick around! This crowd of vitamins includes vitamin C and the big group of B vitamins — B1 , B2 , B6 , B12 and so on.