Ladies and gentlemen, please fasten your seat belts. The plane _______.

A．takes off

B．is taking off

C．has taken off

D．took off

下列哪项符合克罗恩病的特点（）

A.病变呈连续性

B.病变在回肠末段及近段结肠

C.病变累及肠壁全层

D.常有瘘管形成

E.大便呈糊状，无脓血