如图，平行四边形ABCD中，点E是BC边上的点，BE：EC＝1：2，AE与BD交于点O，如果 ， ，那么 ＝(用向量 、 表示)．

为了使水污染物治理达标排放，含下列哪种元素的化合物的洗衣粉已不准使用（　　）

部分高海拔地区昼夜温差较大，为了保护秧苗在夜间不被冻坏，人们常在傍晚往农田中灌水，白天再将水放出，这是利用水的较大的特性。如果让2000kg的水温度下降1℃，放出的热量为J。[c_水=4.2×10³J/（kg·℃）]

解方程：

以下是对不同工作人群的睡眠模式的调查结果，请根据调查表信息补全报告内容。

	Student	Truck driver	Full-time mother	Business executive (企业主管)	Doctor
Sleeping time	9 hours	6 hours	8 hours	6 hours	5 hours
Bedtime hours	10 pm-7 am	7 am-10 am 4 pm-7 pm	3 am-6 am 1 pm-3 pm 10 pm-1 am	11 pm-5 am	1 am-3 am 4 am-7 am

    The table above shows the sleeping patterns (模式) of people doing  jobs. It is clear that there are big differences among them. For example, students continuously (连续地) sleep for each night because they go to school during the day.  are busy and stressed out, so they only sleep for 6 hours. But they also sleep continuously during the night. Truck drivers sleep 6 hours and doctors sleep the  hours among the five. However, because of their jobs, they have to divide their bedtime into different periods. Finally,  mothers sleep when their babies do. They often have to wake up during the night to comfort (安抚) their babies. It is important to consider sleeping patterns when choosing a job.

如图，一次函数y＝x+4的图像与反比例函数 （k为常数且k≠0）的图像交于A（－1，a），B（b，1）两点，与x轴交于点C.

2020年，教育部在门户网站、“微言教育”政务等新媒体等平台开展“我为教育‘十四五’规划提建议”建言建议征集活动。这有利于（    ）

①保证人民当家作主  
②人民直接行使国家权力 
③公民参与民主生活  
④激发公民的主人翁意识

小明把安装完成的直流电动机模型接入如图所示的电路中，闭合开关并调节滑动变阻器，电动机正常转动，若要改变电动机转动方向，下列做法中无效的是（   ）

如图，一艘海轮位于灯塔P的北偏东方向55°，距离灯塔为2海里的点A处．如果海轮沿正南方向航行到灯塔的正东位置B处，海轮航行的距离AB长是（    ）

下列反应中，属于化合反应的是（  ）

汶川地震后的5月14日，我空降兵15勇士不畏牺牲，勇敢地从4999m的高空跳伞执行侦查营救任务，为上级决策提供了第一手资料，为组织大规模救援赢得了宝贵时间，受到了中央军委的通令嘉奖。跳伞勇士在空中匀速下落的过程中，他的(       )

高铁每节车厢都有两间洗手间，只有当两间洗手间的门都关上时（每扇门的插销都相当于一个开关），车厢中指示牌内的指示灯才会发光提示旅客“洗手间有人”。请你设计上述电路，并将电路图画在图中方框内。

下图所示的四个图像，能正确反映对应变化关系的是（   ）

阅读理解

    Do you know what Oscar is? When did it start? Maybe you can find the background of the awards in the following passage.

    The awards started in 1929. Their full title is "The Academy of Motion Picture Arts and Sciences Awards". The Academy is a group of people who have worked in the film industry for many years. They decide who will receive the awards. The awards are often referred to as the " "Oscar". This is a nickname given to the awards by a lady called Margaret Herrick. She was once the director of the Academy and she once said that the little gold statue reminded her of her uncle Oscar!

    The Oscar is always an exciting event. Each year, at least one unusual thing happens. When the Italian actor and director Roberto Benigni won an Oscar for best foreign film, he danced on stage! When Gwyneth Paltrow, the star of Shakespeare in Love won the Oscar for best actress, she could not make her acceptance speech because she was crying so much with happiness!

    In 1987, Bernardo Bertolucci won the award for best director for a film about the last emperor of China. Since then, Chinese film and actors have started to make an impact at the awards. Crouching Tiger, Hidden dragon was a huge success and it won the award for best foreign language film in 2001. It also won several technical awards for its amazing "flying," people. We expect to see more awards for Chinese film in the near future.

    It's time for the Oscar again. Once more, the stars will dress up in their finest and go to Kodar Theatre. There, they will find out who have won the awards for best actor, best actress and best director. Millions of people watch the awards every year to find out who the winners are. Some people watch it to see the stars crying and laughing as they receive their awards.

 下列物质分类不正确的是（　　）

匈牙利改革取得成效的根本原因是(   )

湿法炼铜为我国首创。早在西汉时期，就有从胆矾水溶液中置换出铜的记载，其反应的化学方程式为：Fe+CuSO₄═Cu+FeSO₄ ． 若采用此法炼制128t铜，需要消耗铁的质量是多少？

图甲是小灯泡的电压——电流图像。将此灯泡L与滑动变阻器R串联在电压为4.5V的电路中（如图乙），闭合开关，移动滑片P ， 当小灯泡的功率为0.75W时，（   ）

对下列事实的解释，合理的是（   ）

一种在阳光下能不断摇摆的塑料小花。花盆表面的太阳能电板在光照下，产生电流驱动电动机，使小花左右摆动。下列有关该小花摆动过程中能量转化的描述正确的是（ ）