题目

阅读下面短文，从短文后各题所给的四个选项(A、B、C和D)中，选出可以填入空白处的最佳选项。 Number sense is not the ability to count. It is the ability to recognize a 1 in number. Human beings are born with this ability.2, experiments show that many animals are, too. For example, many birds have good number sense. If a nest has four eggs and you remove one, the bird will not3. However, if you remove two, the bird4leaves. This means that the bird knows the5between two and three. Another interesting experiment showed a bird's6number sense. A man was trying to t 一个小服装厂生产某种风衣，月销售量x(件)与售价P(元/件)之间的关系为P=160－2x,生产x件的成本R=500+30x元 (1)该厂的月产量多大时，月获得的利润不少于1300元？ (2)当月产量为多少时，可获得最大利润？最大利润是多少元？