简述家畜性机能发育的阶段（公畜、母畜）。
参考答案：
公畜性机能发育阶段：
初情期、性成熟期。
母畜性机能发育阶段：
初情期、性成熟期、繁殖能力停止期。
—Do you know her well?
—Sure.We___________ friends since 10 years ago. [ ]
A. were
B. have made
C. have been
D. have became
下列哪种疾病的疼痛不能定位
A．急性牙髓炎B．牙本质敏感症C．急性根尖炎D．急性牙周脓肿E．急性龈 * * 炎
