求用英文介绍下小肠 （位置及功能等）简单些也可,

The small intestine (or small bowel) the part of the gastrointestinal tract following the stomach and followed by the large intestine,and is where much of the digestion and absorption of food takes place.
Digestion in the lower part of the small intestine
(a)Tiny glands in the small intestine produce intestinal juice which contains several types of digestive enzymes.
(b)Carbohydrates such as maltose are converted to simple sugars,polypeptides to amino acids and fats to fatty acids and glycerol.
Absorption of digested food
(a)The movement of digested food through the walls of the small intestine into the blood capillaries is called digestion.
(b)Absorption takes place because of diffusion.
(b)The internal surface of the lower part of the small intestine is covered by finger-like projections called villi.The villi increase the surface in contact with digested food.Food can be absorbed at a faster rate.
(b)The small intestine is about 7m long.This ensures that most of the digested food has been absorbed before reaching the large intestine.
(e)The walls of the small intestine are richly supplied with blood vessels to carry away the digested food.
以上的地址有详细资料,上面我给出的答案已经整理出了重点.
Small intestine：小肠
Gastrointestinal tract：肠胃道
Large intestine：大肠
Digestion：消化
Absorption：吸收
Glands：腺
Enzymes：酶
Carbohydrates：碳水化合物
Maltose：麦芽糖
Simple sugars：单糖
Polypeptides：肽
Amino acid：氨基酸
Fatty acids：脂肪酸
Glycerol：甘油
Blood capillaries：微血管
Diffusion：渗透作用
Villi：绒毛
Blood vessels：血管