下列实体的联系中，属于多对多联系的是______。A．学生与课程 B．学校与校长 C

Here is my idea about how a friend is like. Firstly, 61.______a friend is someone you can share your secrets. If you 62.______tell him a secret, never will he talks about it with anybody 63.______else. Besides, a friend is always good listener when you 64.______need one. After hear your sad stories, he will say some 65.______words that is nice and warm. Still, your happiness makes 66.______him happily, too. What’s more, a good friend is willing to 67.______offer the help to which you need, or can at least give you 68.______some advices. In a word, friends are those you like and 69.______trust, and you will enjoy every minute that you spent with 70.______them.

62().

男31岁，尿频、尿急、尿痛1年余，有时尿浑浊，服用多种抗生素治疗无效，尿液检查：脓细胞满视野，蛋白（++）。B超提示右肾积水，输尿管探测不清楚。

最为适宜的治疗方法是（）。

A.抗结核药物治疗

B.加强营养，卧床休息

C.口服异烟肼1周手术治疗

D.诊断明确立即切除肾脏

E.口服异烟肼、利福平、吡嗪酰胺2周后切除右侧肾脏

图中所示为某晶闸管变流器供电的直流电动机速度调节系统的结构图，直流电动机规格为：额定功率p_e=1500kW，额定电压U_e=750V，额定电流I_e=2100A，额定转速n_e= 450r/min，最大转速n_max=900r/min，最大弱磁倍数k=900/450=2，允许最大过电流倍数，传动系统的飞轮矩GD₂=6475N·m²。电枢回路电阻R_ds=0.005Ω，电枢电感I_ds=1.0mH。晶闸管采用三相桥式整流回路，晶闸管交流器的标幺放大系数为1.1。

该系统电枢回路的时间常数T_da最接近于（）s。

A．0.2

B．5

C．200

D．2

简述花店的经营管理

关于天气系统与天气的叙述正确的是（）

A.冷锋在我国一年四季都有

B.暖锋过境后形成连续性降雨

C.气旋带来狂风、暴雨天气

D.反气旋控制是寒冷干燥天气