骨折修复的骨痂中，矿物盐沉着是由于哪种物质作用的结果

A．维生素C

B．碱性磷酸酶

C．负重的刺激

D．电位差

E．透明质酸酶

Our car ______ on our way to school, so we had to walk there.

A．broke up

B．broke off

C．broke down

D．broke away