The heart pumps blood to all parts of the body through a system of arteries and veins 心脏通过动脉和静脉供血到全身
It's located in the chest，between the lungs，and beats about once per second 它在胸口里两肺之间，每秒跳动一次
The kidneys remove waste and toxins from the blood.they are bean shaped organs and are about 10 centimeters long and 6 centimeters wide 肾从血液里排出废物和毒素，它们是豆子形状的器官大约长10厘米宽6厘米
The lungs exchange oxygen from the air with carbon dioxide from the blood，they expand when inhaling air ，and contract when exhaling air 肺用血液里的二氧化碳与空气中的氧气置换.当吸气时 它们扩张，当呼出气时它们收缩
Exchange A with B ：用B 跟A 交换
The stomach is below the heart，and its part of the digestive system. it uses acids to digest food before passing it to the small intestine 胃在心脏的下面，他是消化系统一部分，进入小肠前它用胃酸消化食物
The bladder is a balloon shaped organ that collects urine from the kidneys. in an adults the bladder can hold about half a liter of urine 膀胱是气球形状的器官，从肾里收集尿液，在成年人的膀胱能保存大约半升的尿液
