烧结生产中要求热返矿+5mm粒级含量小于（）为宜。
参考答案：15%
The manager urged older staff ________early retirement and new staff _______ more time for work.
A．take up; to set aside
B．took up; set aside
C．would take up; to lay aside
D．must take up; lay aside
KY-310型牙轮钻机液压系统主泵溢流阀为（）。
