乳牛，食欲减少，口腔干臭，鼻镜干燥，反刍停止。肠蠕动音减弱，排粪停止。两后肢交替踏地或蹴腹，该牛所患的疾病是（）

A.肠炎

B.口炎

C.酮病

D.肠便秘

E.前胃弛缓

Wherever one works, as a teacher, he or she should be erudite, patient and helpful.

A．strict

B．knowledgeable

C．considerate

D．serious