根据中铁四人（2014）755号文规定，子分公司项目部的超额利润奖励（）奖励项目部班

以下提供若干个案例，每个案例下设若干个考题。请根据各考题题干所提供的信息，在每题下面的A、B、C、D、E五个备选答案中选择一个最佳答案。

男，52岁，便血3个月，为鲜红色，不伴肛门及下腹疼痛，无大便习惯改变

接诊首选检查是

A．便常规及大便隐血

B．肛门镜检查

C．乙状结肠镜检查

D．钡灌肠

E．纤维结肠镜检查

光度准确度

在特殊情况下，“应收账款”和“应付账款”账户都可能成为资产负债结算账户。（）

氮是地球上含量丰富的一种元素，氮及其化合物在工农业生产、生活中有着重要作用．请回答下列问题：

（1）用CH₄催化还原NO_x可以消除氮氧化物的污染．例如：

CH₄（g）+4NO₂（g）=4NO（g）+CO₂（g）+2H₂O（g）△H₁=-574kJ•mol^-1

CH₄（g）+4NO（g）=2N₂（g）+CO₂（g）+2H₂O（g）△H₂

若1mol CH₄还原NO₂至N₂，整个过程中放出的热量为867kJ，则△H₂=______；

（2）工业合成氨气需要的反应条件非常高且产量低，而一些科学家采用高质子导电性的SCY陶瓷（能传递H⁺ ）实现氨的电化学合成，从而大大提高了氮气和氢气的转化率．电化学合成氨过程的总反应式为：N₂+3H₂ 

通电      .

一定条件

 2NH₃，则在电化学合成氨的过程中，阴极反应式为______；

（3）在一定条件下，将l mol N₂与3mol H₂混合于一个10L密闭容器中，反应达到平衡时，A点混合气体中氨占25%，

试回答：①N₂的转化率为______；

②右图中在状态A时，平衡常数 K_A______（填写代入数值的表达式，不要求算出具体数值）；当温度由T₁变化到T₂时，K_A______ K_B（填“＞”、“＜”或“=”）．

③在容积固定的密闭容器中发生上述反应，各物质的浓度如下表：

时间/min 浓度/mol．L	c （N2）	c （H2）	c （NH3）
0	0.6	1.8	0
3	0.52	x	0.16
6	0.36	1.08	0.48
9	0.36	1.08	0.48

反应从0min到3min之间，H₂的反应速率为______；反应在3min时，条件发生了改变，改变的条件可能是______ （填序号）．

a．使用催化剂  b．降低温度  c．增加H₂的浓度．

We once had a poster competition in our fifth grade art class.

"You could win prizes," our teacher told us as she wrote the poster information on the blackboard. She passed out sheets of construction paper while continuing. "The first prize is ten dollars. You just have to make sure that the words on the blackboard appear somewhere on your poster. "

We studied the board critically. Some of us looked with one eye and held up certain colors against the blackboard rocking the sheets to the right or left while we conjured up our designs. Others twisted their hair around their fingers or chewed their erasers while deep in thought. We had plans for that ten-dollar grand prize, each and every one of us. I’m going to spend mine on candies one hopeful would announce while another practiced looking serious wise and rich.

Everyone in the class made a poster. Some of us used parts of those fancy paper napkins, while others used nothing but colored construction paper. Some of us used big designs and some of us preferred to gather our art tidily down in one comer of our poster and let the space draw the viewer’s attention to it. Some of us would wander past the good students’ desks and then return to our own projects with a growing sense of hopelessness. It was yet another grown up trick of the sort they seemed especially fond of making all of us believe we had a fair chance and then always—always—rewarding the same old winners.

I believe I drew a sailboat, but I can’t say that with any certainty. I made it. I admired it. I determined it to be the very best of all of the posters I had seen and then I turned it in.

Minutes passed.

No one came along to give me the grand prize and then someone distracted me and I probably never would have thought about that poster again.

I was still sitting at my desk thinking, what poster When the teacher gave me an envelope with a ten-dollar bill in it and everyone in the class applauded for me.

After seeing the good students’designs, some students （）.

A．loved their own designs more

B．thought they had a fair chance

C．put their own designs in a comer

D．thought they would not win the prize