沙眼的局部用药的疗程最少为（）
A.1～2周
B.10～12周
C.半年
D.半年～1年
E.1个月
参考答案：B
3月龄牛，连续数日体温42.1～42.5℃，反复咳嗽，呼吸困难。胸部叩诊出现大片浊音区。该牛最可能患的疾病是（）
A.肺结核
B.支气管炎
C.大叶性肺炎
D.小叶性肺炎
E.肺充血和肺水肿
By the time Jack returned home from England, his son. from college.
A．graduated
B．has graduated
C．had been
D．had graduated
eturned home from England, his son. from college.