Carl is studying       food science at college and hopes to open up      meat  processing factory of his own one day.

A．/;the

B．the; a

C．/;a

D．the; the

HIV的传播方式不包括（）

A.性接触传播

B.输血传播

C.垂直传播

D.接触传播

E.使用生物制品