伤寒的潜伏期为_________,平均为_________。
参考答案:7~23天;10~14天
—Thank you for giving us a wonderful Chinese dinner, Ms. Wang.
—__________________.
A.Oh. I’m afraid I didn’t cook very well.
B.I’m glad you enjoy it.
C.Come again when you are free.
D.It’s not polite of you to say so.
按照经济学中的市场结构理论,在寡头垄断市场上,当产品无较大差异时,为取得更多利润,寡头生产者往往( )。
A.展开价格竞争
B.倾向于非价格竞争
C.在定价方面进行勾结
D.进行质量和数量竞争