题目内容
（请给出正确答案）
生产可能性曲线凹向原点反映了（）。
A．资源在所有生产活动中都同样有效率
B．资源间的不完全替代导致机会成本的递增
C．失业率高
D．政府决策失误
简答题官方参考答案
（由简答题聘请的专业题库老师提供的解答）
更多“生产可能性曲线凹向原点反映了（）。 A．资源在所有生产活动中都同样有效率 B．资源间的不”相关的问题
A．一国资源总能被充分利用
B．假定所有经济资源能得到充分的利用，则只有减少Y物品的生产才能增加X物品的生产
C．改进技术引起生产可能性曲线向内移动
D．经济能力增长唯一决定于劳动力数量
A．一国资源总能被充分利用
B．假定所有经济资源能得到充分的利用，则只有减少Y物品的生产才能增加X物品的生产
C．改进技术引起生产可能性曲线向内移动
D．经济能力增长唯一决定于劳动力数量
单一神经纤维动作电位的幅度
A.不随刺激强度的变化而变化
B.不随细胞外Na+浓度的变化而改变
C.不随传导距离而改变
D.不随细胞的种类而改变
E.不随细胞所处环境温度的变化而变化
本题为多选题，请选出正确答案，谢谢！
A．11．79
B．10．18
C．9．21
D．13.75
The only solid piece of scientific truth about which I feel totally confident is that we are profoundly ignorant about nature. I regard this as the major discovery of the past hundred years of biology. It is, in its way, an illuminating piece of news. It would have amazed the brightest minds of the 18th century Enlightenment to be told by any of us how little we know and how bewildering seems the way ahead. It is this sudden confrontation with the depth and scope of ignorance that represents the most significant contribution of the 20th century science to the human intellect. In earlier times, we either pretended to understand how things worked or ignored the problem, or simply made up stories to fill the gaps. Now that we have begun exploring in earnest, we are getting glimpses of how huge the questions are, and how far they are from being answered. Because of this, we are depressed. It is not so bad being ignorant if you are totally ignorant; the hard thing is knowing in some detail the reality of ignorance, the worst spots and here and there the not-so-bad spots, but no true light at the end of the tunnel nor even any tunnels that can yet be trusted.
But we are making a beginning, and there ought to be some satisfaction. There are probably no questions we can think up that can't be answered, sooner or later, including even the matter of consciousness; to be sure, there may well be questions we can't think up, ever, and therefore limits to the reach of human intellect, but that is another matter. Within our limits, we should be able to work our way through to all our answers, if we keep at it long enough, and pay attention.
The author claims that good science ______.
A．defies prediction
B．should study the unknown
C．should discover scientific truth
D．should offer choices rather than prescribe
警告：系统检测到您的账号存在安全风险
为了保护您的账号安全，请在“简答题”公众号进行验证，点击“官网服务”-“账号验证”后输入验证码“”完成验证，验证成功后方可继续查看答案！
