人的密度与水的密度相当，试估算一个中学生整个身体的体积大约是（　　）

A．5m³

B．50dm³

C．50cm³

D．50mm³

Many lifestyle patterns do such()great harm to health that they actually speed up ()weakening of the human body．

A．a；/

B．/；the

C．a；the

D．/；/