跳汰操作时,加大风量能减弱下降期的吸啜作用。
参考答案:错
The government has taken measures air quality. [ ]
A. to improve
B. improved
C. being improved
D. to be improved
补充(),可以提高青年母牛的繁殖力。
A、蛋白质
B、维生素A
C、矿物质
D、铁