小儿胸腺影像正确的是（）

A.位于前上纵隔

B.上缘界限不清

C.随呼吸改变形态

D.随体位改变形态

E.船帆征为病理特点

Not only his parents but also his grandfather ________ to a lot of places of interest in our country since they came here.

A．has gone

B．has been

C．have gone

D．have been