一早产儿，生后母乳喂养，每次吃奶后有少量奶汁回出，生长发育情况良好．最可能的原因是

A．溢乳

B．胃食道反流

C．幽门痉挛

D．幽门肥厚

E．喂养不当

To be frank, I really don’t know what SOS ____________. Can you explain it?

A．stands by

B．stands for

C．stands up

D．stands with