机械加压送风系统采用内表面光滑的混凝土等非金属材料风道时,其风速不应大于( )。
A.10m/s B.15m/sC.20m/s D.25m/s
参考答案:B
—Excuse me. Is there ________ pay phone near here?
—Yes. You can find one near the bus stop. [ ]
A. an
B. the
C. a
D. /
采购计划的内容是()。
A.采购需求计划
B.采购认证计划
C.采购订单计划
D.采购预算计划