SG1025—170.5—540／540型锅炉共装有（）只煤粉仓燃烧器，另有（）只重油燃烧器和（）只轻油点火器。
参考答案：6×4；3×4；9×4
They began to think about what use could be ________ such materials.
made up B. made from
C. made of D. made out
我国对外关系的基本原则是什么？
