The heart is this incredibly smart machine , it beats seventy to eighty times a minute , and in the space of ......each beat sends de-oxygenated blood to your lungs , and oxygenated blood to all your organs .
The heart is this incredibly smart machine , it beats seventy to eighty times a minute , and in the space of ......each beat sends de-oxygenated blood to your lungs , and oxygenated blood to all your organs .
（心脏是非常聪明的器官，它每分钟跳动70到80下，每次跳动都会将无氧的血液送到肺，将有氧的血液送到全身的器官。）