患儿男，1个月。反复呕吐1周，呕吐发生于进食后10～30分钟，呈喷射性，不含胆汁；查体：一般情况好，无脱水征，上腹可见胃蠕动波，右上腹可触及包块。

为明确诊断，首选的辅助检查是（）

A.腹部B超

B.钡餐

C.胃镜

D.腹部CT

E.腹部平片

We saw several natives advancing towards our party, and one of them came up to us, __________ we gave some bells and glasses.

A．to which

B．to whom

C．with whom

D．with which