You have to leave now_______ you can catch the early bus.

A．although

B．so that

C．because

D．as soon as

属先天性颈部瘘管的是

A．胸导管瘘

B．鳃裂瘘

C．气管颈瘘

D．下咽瘘

E．颈淋巴结结核瘘