煤矿井下每几天必须对甲烷超限断电功能进行测试？

发现法是一种旨在培养学生的探究思维能力的教育方法，其过程因学科不同而异，至少包括以下哪些环节（）

A．分析、比较并提出假设

B．从事操作，验证假设

C．评估教学结果

D．引起学生兴趣，形成探究动机

关于急性湿疹下列哪项正确

A．致病因素易查清 B．皮疹局限
C．皮疹单一
D．渗出明显时用溶液湿敷
E．较快痊愈

For me, scientific knowledge is divided into mathematical sciences, natural sciences or sciences dealing with the natural world (physical and biological sciences), and sciences dealing with mankind (psychology, sociology, all the sciences of cultural achievements. every kind of historical knowledge).

Apart from these sciences is philosophy, about which we will talk later. In the first place, all this is pure or theoretical knowledge, sought only for the purpose of understanding, in order to fulfill the need to understand that is intrinsic and con-substantial to man. What distinguishes man from animals is that he knows and needs to know. If man did not know that the world existed, and that the world was of a certain kind, that he was in the world and that he himself was of a certain kind, he wouldn’t be man. The technical aspects or applications of knowledge are equally necessary for man and are of the greatest importance, because they also contribute to defining him as man and permit him to pursue a life increasingly more truly human.

But even while enjoying the results of technical progress, man must defend the primacy and autonomy of pure knowledge. Knowledge sought directly for its practical applications will have immediate and foreseeable success, but not the kind of important result whose revolutionary scope is for the most part unforeseen, except by the imagination of the Utopians. Let me recall a well-known example. If the Greek mathematicians had not applied themselves to the investigation of conic section zealously and without the least suspicion that it might someday be useful, it would not have been possible centuries later to navigate far from shore. The first men to study the nature of electricity could not imagine that their experiments, carried on because of mere intellectual curiosity, would eventually lead to modern electrical technology, without which we can scarcely conceive of contemporary life.

Pure knowledge is valuable for its own sake, because the human spirit cannot resign itself to ignorance. Butt in addition, it is the foundation for practical results that would not have been reached if this knowledge had not been sought disinterestedly.

Notes: intrinsic 固有的。con-substantial 同体的。autonomy 自主性。zealously and without the least suspicion热情地并丝毫也没有想到。for the most part 大部分，主要地。Utopian乌托邦，理想主义。disinterestedly 不偏不倚地。resign oneself to 听任，顺从。

According to the text, the most important advances made by mankind most probably stem from（）

A. innovations

B. the natural sciences

C. technical applications

D. apparently useless information

操作断路器时注意事项的是（）。

A、分、合闸操作时，动作都要果断、迅速，把操作手柄扳至终点位置，使手柄从上到下要连续运动，确定断路器断开后，方可拉开相应的隔离开关

B、合闸时，要注意观察有关指示仪表，若故障还没有排除，应立即切断线路

C、若系统的最大短路容量超过分断容量时，一旦发生短路，断路器可能爆炸，则应在分、合闸操作前考虑分断容量能否满足要求，如不能满足时应降低短路容量

D、操作隔离开关时，必须先确认断路器已经合闸，并在断路器的操作手柄悬挂“不可断开”的警告牌后，才能操作隔离开关

物体上任一点的投影，就是通过该点所作投射线与投影面的（）。

A、交点

B、交线