【单选题】A country produces only cans of soup and pens and it is producing at a point on its bowed out PPF. If the country increases the production of soup, the opportunity cost of an additional _________.
C.
can of soup is constant
【判断题】由于胶囊壳的保护作用,刺激性强的药物可考虑制成胶囊剂。( )
【简答题】O. Henry was the pen name of American writer Sydney Porter, whose sores, arc famous for their surprise endings, to the point that such an ending is often mentioned as an ‘o. Henry ending’ He was born ...
【单选题】1喷油泵柱塞偶件磨损后其供油提前角的调整措施是( )。