(2012·安徽)Carl is studying ________ food science at college and hopes to open up ________ meat processing factory of his own one day.

A．/；a

B．/；the

C．the；a

D．the；the

锅炉具有爆炸性。锅炉在使用过程中发生破裂，使内部压力瞬时降至( )外界大气压的现象叫爆炸。

A．大于

B．等于

C．小于

D．无法确定