No product is allowed to go into the market if it fails to _____ the quality standard.

A．live

B．come up to

C．meet

D．go through

易导致大出血的消化性溃疡，最常见的部位是

A．幽门

B．胃小弯

C．十二指肠下段

D．十二指肠球部后壁