平面导板矫治器的适应症是（） A.后牙反 B.前牙反 C.牙列拥挤 D.前牙过高，后

【预备知识】 ①对给定的字符集合及相应的权值，采用哈夫曼算法构造最优二叉树，并用结构数组存储最优二叉树。例如，给定字符集合{a，b，c，d}及其权值2、7、4、5，可构造如图5-6所示的最优二叉树和相应的结构数组Ht(数组元素Ht[0]不用)。

结构数组Ht的类型定义如下： #define MAXLEAFNUM 20 struct node{ char ch;/*当前节点表示的字符，对于非叶子节点，此域不用*/ int weight; /*当前节点的权值*/ int parent; /*当前节点的父节点的下标，为0时表示无父节点*/ int lchild,rchild; /*当前节点的左、右孩子节点的下标，为0时表示无对应的孩子节点*/ }Ht[2*MAXLEAFNUM]; ②用“0”或“1”标识最优二叉树中分支的规则是：从一个节点进入其左(右)孩子节点，就用“0”(“1”)标识该分支(示例见图5-6)。 ③若用上述规则标识最优二叉树的每条分支后，从根节点开始到叶子节点为止，按经过分支的次序，将相应标识依次排列，可得到由“0”、“1”组成的一个序列，称此序列为该叶子节点的前缀编码。例如图5-6所示的叶子节点a、b、c、d的前缀编码分别是110、0、111、10。 【函数5-6说明】 函数void LeafCode(int root，int n)的功能是：采用非递归方法，遍历最优二叉树的全部叶子节点，为所有的叶子节点构造前缀编码。其中形参root为最优二叉树的根节点下标，形参n为叶子节点个数。 在构造过程中，将Ht[P].weight域用做被遍历节点的遍历状态标志。 【函数5-6】 char **Hc; void LeafCode(int root, int n) /*为最优二叉树中的n个叶子节点构造前缀编码，root是树的根节点下标*/ {int i,p=root,cdlen=0;char code[20];Hc=(char**)maloc((n+1)*sizeof(char*)); /*申请字符指针数组*/for(i=1;i＜=p;++i) Ht[i].weight=0; /*遍历最优二叉树时用做被遍历节点的状态标志*/while(p){/*以非递归方法遍历最优二叉树，求树中每个叶子节点的编码*/ if(Ht[p].weight==0){/*向左*/ Ht[p].weight=1; if(Ht[p].lchild !=0){ p=Ht[p].lchild; code[cdlen++]=’0’; }else if(Ht[p].rchild==0){ /*若是叶子节点，则保存其前缀编码*/ Hc[p]=(char *)malloc((cdlen+1)*sizeof(char)); (1) ; strcpy(Hc[p],code); } }else if(Ht[p].weight==1)(/*向右*/ Ht[p].weight=2; if(Ht[p].rchild !=0){ p=Ht[p].rchild; code[edlen++]=’1’; } }else { /*Ht[p].weight==2，回退*/ Ht[p].weight=0; p= (2) ; (3) ; /*退回父节点*/ }}/*while结束*/ } 【函数5-7说明】 函数void Decode(char *buff,int root)的功能是：将前缀编码序列翻译成叶子节点的字符序列，并输出。其中形参root为最优二叉树的根节点下标，形参buff指向前缀编码序列。 【函数5-7】 void Decode(char *buff,int root) {int pre=root,p;while(*buff !=’\0’){ p=root; while(p !=0){/* 存在下标为p的节点*/ pre=p; if( (4) )p=Ht[p].lchild; /*进入左子树*/ else p=Ht[p].rchild; /*进入右子树*/ buff++; /*指向前缀编码序列的下一个字符*/ } (5) ; printf("%c",Ht[pre].ch);} }

阅读下面短文，从短文后所给的四个选项（A,B,C和D）中，选出可以填人空白处的最佳选项，并在答题卡上将该项涂黑。

It was one of the hottest days of the dry season. We had not seen  36  for almost a month. The crops were dying. Every day, my husband  37  to get water to the fields. But  38  we saw some rain soon, we would lose everything.

However, one day I learned the true lesson of  39  and witnessed the only miracle I had  40  seen before. I was cooking in the kitchen when I saw my son, Billy,  41  toward the woods. He was walking  42  with effort, trying to be as still as possible. Minutes after he disappeared into the  43 , he came running back. I went on cooking, 44  that whatever he had been doing was finished. Moments later,  45 , he was once again walking slowly toward the woods. This activity went on for an hour. Finally I couldn’t help  46  him and saw the most amazing  47 .

Several large deer stood in front of him. Billy walked right up to them. I  48  screamed(尖叫) for him to get away, because a huge deer was dangerously  49  to him at that time. But the deer didn’t even move as Billy knelt down(跪下). I saw a tiny  50  lying on the ground, obviously suffering from  51 , lifting its head to drink the water cupped in Billy’s hands. When the water was  52 , Billy ran back to get more. It then became quite  53  to me what my son was doing.

I stood there, watching my  54  boy working so hard to save another life. As my tears began to hit the ground, they were suddenly joined by other drops. I looked up at the sky. It was as if God himself was weeping with pride. The rain that day 55 our farm.

36. A. water               B. rain             C. cloud           D. storm

37. A. decided           B. chose           C. tried            D. offered

38. A. before            B. if                  C. until           D. unless

39. A. sending          B. sharing          C. forgiving        D. begging

40. A. ever             B. never           C. once              D. yet

41. A. running                                         B. jumping         C. walking               D. riding

42. A. slowly                                          B. quickly          C. hurriedly              D. dangerously

43. A. plants           B. flowers          C. vegetables       D. woods

44. A. thinking         B. wondering       C. worrying        D. dreaming

45. A. though           B. besides          C. however           D. too

46. A. beating          B. following       C. teaching           D. hoping

47. A. sign             B. field             C. world           D. scene

48. A. almost           B. already          C. just              D. even

49. A. weak            B. ill               C. close            D. brave

50. A. horse                                           B. crop               C. baby              D. deer

51. A. thirst            B. diseases           C. heat             D. pain

52. A. lost             B. cleaned           C. gone            D. dried

53. A. comfortable                                     B. clear               C. acceptable         D. simple

54. A. kind                                           B. clever              C. naughty          D. honest

55. A. hit              B. washed            C. ruined           D. saved

下列关于实验室测试评价论述错误的是（）

A.包括整体动物实验和体外测试系统

B.常用于测试化学物毒性，预示对人的危害

C.评价有害因素潜在作用

D.结合临床观察结果，阐明接触水平-反应关系

E.制订人体参考界限值

物流设施标准包括（）

A.物流设施设备基础标准

B.物流设施

C.集装化器具

D.物流设备

E.物流信息标准

初产妇第一产程活跃期停滞是指进入活跃期后宫口不再扩张超过()。

A．1小时

B．1小时30分

C．2小时

D．2小时30分

E．3小时