成本不变行业
参考答案：
是指随着行业中厂商数量（或者行业中总产量的增加，厂商的成本不发生变动的行业。该行业的长期供给曲线是一条水平的直线。
43000千克+4吨=______千克．
根据句意和汉语注释，在相应的横线上，写出单词的正确形式。
小题1:The hostess （点头）to show that she agreed with us at the show.
小题2:I am often (提供) some useful help by my teachers and classmates.
小题3:I have ordered several ________(册)of this book from abroad. Would you like to have one?
小题4:Can this kind of robot be (可获得的) in the nearest supermarket?
