单选题设A为n×m矩阵，A以列分块，记A=(α 1 ，α 2 ，…，α i ，…，α m )，在A中划去第i列得到的矩阵记为B，B=(α 1 ，α i-1 ，α i+1 ，…，α m )，则R(A)=R(B)是α i 可以由B的列向量线性表示的______．

单选题如果紫色不代表社区，那么黄色不代表幸福；如果紫色代表社区，那么绿色代表海港；蓝色不是代表社区，就是代表环境；紫色或者代表社区，或者代表海港；黄色代表幸福。一种颜色只能代表幸福、社区、海港、环境中的一种。 据此，可以推断出以下哪一项正确?

单选题当一个国家出现通货膨胀或经济过热时，政府常常采取收紧银根、提高利率、提高贴现率等紧缩的货币政策进行调控。但是，1990年，日本政府为打压过高的股市和房地产泡沫，持续提高贴现率，最后造成通货紧缩，导致日本经济十几年停滞不前。1995年至1996年，泰国中央银行为抑制资产价格泡沫，不断收紧银根，持续提高利率，抑制了投资和消费，导致经济大衰退。 以下哪项陈述最适合作为上述论述的结论?

单选题若∫f(x)dx=F(x)+C，则∫f(ax2+b)xdx=______．A．F(ax2+b)+CB．C．D．2aF(ax2+b)+C

单选题表述1：企业的资本包括其股票和债券。表述2：经济学家不把购买企业股票看成一项投资。下列说法正确的是( )。

单选题货币政策的中介目标是__________。

单选题 根据哈罗德的分析，如果有保证的增长率大于实际增长率G，经济将（ ）。 A、持续高涨 B、长期萧条 C、均衡增长 D、不能确定

单选题Making good coffee is not a simple business. Coffee bushes must be grown in shade. A hillside is best--but it mustn't be too (1) . After three years, the bushes will start to (2) bright-red coffee "cherries", which are picked, processed to (3) the inner part, and spread out to dry for days, (4) on concrete. They are (5) again to separate the bean, which needs to rest, preferably for a few months. Only then can it be roasted, ground and brewed (6) the stuff that dreams are suppressed with. In Mexico and parts of Central America, (7) in Colombia, most coffee farmers are smallholders. They found it especially hard to (8) the recent fall in the coffee price. The (9) of their income makes it hard for farmers to invest to (10) their crop, says Fernando Celis. The fall forced many small farmers to (11) other crops, or migrate to cities. For farmers, one way out of this (12) is to separate the price they are paid (13) the international commodities markets. This is the (14) of Fair-trade, an organization which certifies products as "responsibly" sourced. Fair-trade determines at what price farmers make what it considers a (15) profit. Its current (16) is that the appropriate figure is 10% above the market price. (17) , sales of Fair-trade-certified coffee have increased from $ 22. 5m per year to $ 87m per year since 1998. This is still a tiny fraction of the overall world coffee trade, worth $10 billion (18) But there are plenty of other markets for high-quality coffee. Some small producers can (19) more by marketing their coffee as organic or "bird-friendly" because, unlike large, mechanized plantations, they have (20) shade trees.

单选题在一些国家，不少家庭医生既上门为社区里的富人服务又上门为社区里的穷人服务，不过对富人的收费高于穷人，这是因为（）。

单选题资本最一般的和初始的形态是指（ ）。

单选题肥皂是用油脂和烧碱经过煮制加工而成的，肥皂含有30%左右的水分，如果对它进行晾晒，不仅会使水分蒸发而收缩干裂，还会使内部的油脂和烧碱分离，结果油脂变成酸酯，烧碱因吸收空气中的二氧化碳而变为纯碱，使肥皂的去污能力降低。 由此可以推出：

单选题老王的四个儿子中有一人买彩票中了大奖。有人问他们时，老大说“中大奖的可能是老三也可能是老四”；老二说“老四中了大奖”；老三说“我没有中大奖”；老四说“中大奖的肯定不是我”。了解儿子的老王说：“他们中有三位不会说谎话。” 若老王说的正确，则中大奖者为哪一个儿子?

单选题社会简单再生产的基本实现条件是（ ）。