【单选题】(If) you (will buy) one box at the regular price, you would receive (another one) at (no) extra cost.
【简答题】One for you one for me. [ ] A and B or
【单选题】If you can dream ____, you can do ____.
【单选题】(If) you (will buy) one box at the regular price, you would receive (another one) at (no) extra cost.
【多选题】下列费用中 属于约束性固定成本的 有 ( )