题目

—Would you mind giving your advice on how to improve our business management?        —If you make ______ most of the equipment, there will be ______ rise in production．        A．不填；不填     B．the；a      C．不填；a   D．the；不填 答案：B 解析: 略泡沫钢是含有丰富气孔的钢材料，可作为防弹服的内芯，孔隙度是指泡沫钢中所有气孔的体积与泡沫钢总体积之比。已知钢的密度为7.9×103 kg/m3，一块质量为0.79 kg、边长为1 dm的正方体泡沫钢，孔隙度是A. 1% B. 10% C. 90% D. 99%