若见病人面色为黑色，则为：（） A.虚热证 B.瘀血 C.惊风 D.实热证 E.失血

下列关于全口义齿下颌侧切牙的排列要求正确的是（）

A.唇舌向垂直排列

B.颈部向远中倾斜明显

C.远中稍向舌侧

D.切缘在_平面上

E.切缘与上前牙舌面接触

Howling(吼叫) is a behavior commonly observed among a wolf pack(狼群). As pack animals, wolves work together to hunt and rely on howling as an important means of communication among each other. There’re different explanations of a wolf’s howl and it appears that there may be more to discover．

One theory is that wolves howl to bond better together. It’s almost as if howling together helps the pack stay together. Perhaps something similar to people feeling a sense of involvement with each other when singing a song together. But this theory may be wrong, explains Fred H. Harrington, a professor who studies wolf behavior.

Indeed, there have been times when wolves have been seen one moment howling in a chorus(合唱), and the next, quarreling among each other. It appears that usually the lowest-ranking members of the pack may actually be “punished” for joining in the chorus at times. So is howling a way to strengthen a social bond or just a way to reconfirm status (地位) among its members? Why do wolves howl for sure?

What is clear, however, is that howling is often used among pack mates to locate each other. Hunting grounds are distant and it happens that wolves may separate from one another at times. When this happens, howling appears to be an excellent means of gathering.

Howling, interestingly, is a contagious behavior. When one wolf starts to howl, very likely others will follow. This is often seen to occur in the morning, as if wolves were doing some sort of “roll call” where wolves all howl together to report their

小题1:What is the possible similarity between wolves’ howling together and human’s singing in chorus?

A．The act of calling each other．

B．The sense of accomplishment．

C．The act of hunting for something．

D．The sense of belonging to a group．小题2:Why does Harrington think the “social bond” theory may be wrong?

A．Wolves separate from each other after howling．

B．Wolves tend to protect their hunting grounds．

C．Wolves sometimes have quarrels after howling together．

D．Wolves of low rank are encouraged to join in the chorus．小题3:Researchers are sure that wolves often howl to______．

A．show their ranks

B．find their companions

C．report the missing ones

D．express their loneliness小题4:“Howling… is a contagious behaviour”（in the last paragraph）means_______．

A．howling is a signal for hunting

B．howling is a way of communication

C．howling often occurs in the morning

D．howling spreads from one to another

试绘制低压三相异步电机点动正转控制原理图。

按照题目要求作图：

（1）在图中画出滑轮组最省力的绕线方式。

（2）在图中请在图中画出用此杠杆提升物体时的最小力的示意图（O为支点）。

（3）在图中杠杆OAB处于平衡状态，画出使杠杆平衡的动力的力臂L₁。

地球水圈中总的体积和约为（）亿立方公里。

A.3

B.4

C.5

D.6