种苗行业管理中所指的“四证一签”是什么？
参考答案：
苗木生产许可证、经营许可证、苗木出圃合格证、苗木检疫证和苗木标签。
The officers narrowly escaped in the hot battle. [ ]
A. have killed
B. to kill
C. to be killed
D. being killed
可引起子宫节律性收缩
A．雌激素B．孕激素C．雄激素D．促卵泡素E．黄体生成素
