母猪的初情期是性成熟的（）阶段。
A、初级
B、中级
C、高级
D、排卵
参考答案：A
With respect to discretionary changes in fiscal policy, the time period, between the recognition of the change and the time the policy change is enacted is best described as the（）
A. impact lag.
B. recognition lag.
C. administrative period.
试述精神分裂症的临床诊断标准。
