为何要采用组合式制动梁逐步取代现有的槽钢弓形杆制动梁？

“How did Norman know, Sister Emma?”

“He overheard you and Aryan arguing. I suspect that he purposely overheard on you. Norman knew or concluded what profession Aryan practiced. He might well have followed Aryan on his explorations. Whether he did or not is beside the point. When Aryan came back yesterday afternoon, Norman certainly decided that he had made some find, for Aryan told Norman that he would be leaving for the capital to meet the detective the next morning. He probably followed Aryan to your room and overheard what passed between you.

“Since you could not act against the law of man and God, he would serve a natural justice in his own way. He took the jar of poison hemlock from the chemistry shop and when Aryan asked for a drink, he supplied it. Norman did not know the precise quantity needed and so Aryan did not suffer the full effects until after the bell called the community into the dining hall for the evening meal.”

Abbess was following Sister Emma closely.

“And then?”

“Then I began my investigation, and then the detective arrived seeking Aryan for an explanation for his death.”

“But who killed Norman?”

“Norman knew that sooner or later he would be discovered. But more importantly in his guileless (坦率的) mind there was also the guilt of having taken a man’s life to be considered. Norman was a simple man. He decided that he should accept the punishment—the honor-price of a life. What greater honor-price for the life of Aryan could he offer than his own? He also took a draught of poison hemlock.”

There was a pause.

小题1:What may have happened to Aryan?

A．He was killed by poison.

B．He was found missing.

C．He was poisoned but saved.

D．He went away with what he had found.小题2:What did Abbess do according to Sister Emma when Aryan came back?

A．She talked with Aryan about Norman’s strange actions. .

B．She secretly discussed with Aryan about something secret.

C．She followed the two men and found what they were doing.

D．She let Sister Emma help find out the two men’s secret.小题3:What can we conclude from the above story?

A．Abbess served the detective.

B．Emma knows all the people mentioned.

C．Aryan was sent to kill Abbess but failed.

D．Norman seemed very devoted to Abbess.小题4:Which of the following might be true according to the above passage?

A．Abbess hired Norman to fight against Aryan.

B．Norman told everything to Emma.

C．Aryan worked for the detective.

D．All the people came from the capital.

在操场上，两同学相距L为10 m左右，在东偏北、西偏南11°的沿垂直于地磁场方向的两个位置上，面对面将一并联铜芯双绞线像甩跳绳一样摇动，并将线的两端分别接在灵敏电流计上。双绞线并联后的电阻R为2Ω，绳摇动的频率配合节拍器的节奏，保持f=2 Hz。如果同学摇动绳子的最大圆半径h=1 m，电流计的最大值I=3 mA。

（1）试估算地磁场的磁感应强度的数量级___________，数学表达式B=___________。（用R，I，L，f，h等已知量表示）

（2）将两人的位置改为与刚才方向垂直的两点上，那么电流计的读数为___________。

15世纪后半期，阻碍传统的地中海贸易路线，迫使欧洲航海家探寻通往东方新航路的是 [ ]

A．东罗马帝国

B．奥斯曼帝国

C．蒙古帝国

D．俄罗斯帝国

中央电视台广告经营的经验是将广告建立在媒体品牌的基础上，主要表现在四个方面，以下（）不属于这四个方面之一。

A．依据媒体品牌定位进行广告推广

B．依据客户需求决定营销计划

C．利用品牌推广机会加强广告资源的宣传

D．主动出击联系广告业务

嘉兰为百合科攀援性多年生草本，叶端成卷须状，（），花被片宽大线形，波状扭曲，反卷，上部红色，下部黄色，有纯黄色的品种。

A、花单生或数朵组成伞房花序

B、花单朵互生

C、花单生或数朵组成圆锥花序

D、花单生或数朵组成伞形花序