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恩格尔系数是食品支出总额占个人消费支出总额的比重，其数值越小说明生活富裕程度越高．统计改革开放40年来我国历年城镇和农村居民家庭恩格尔系数，绘制了下面的折线图．根据该折线图，下列结论错误的是（    ）

如图甲所示，质量m=1 kg的小滑块(可视为质点)，从固定的四分之一光滑圆弧轨道的最高点A由静止滑下，经最低点B后滑上位于水平面的木板，并恰好未从木板的右端滑出。已知木板质量M=4 kg，上表面与圆弧轨道相切于B点，木板下表面光滑，滑块滑上木板后运动的v-t图像如图乙所示，取g=10 m/s² ， 求：

如图是初中化学实验常见仪器，回答下列问题：

计算 的结果是.

在单杠上做引体向上时，横杆受力分析正确的是（    ）

下列是有关二倍体生物的细胞分裂信息，请据下图分析回答下列问题。

若一个四位数M的个位数字与十位数字的平方和恰好是M去掉个位与十位数字后得到的两位数，则这个四位数M为“勾股和数”．

例如： 是“勾股和数”.

又如： 不是“勾股和数”

读太平洋的洋流分布略图，回答下列各题。

若关于x的方程 = +1无解，则a的值为（     ）

某校从8名教师中选派4名教师同时去4个边远地区支教（每地1人），其中甲和乙不同去，甲和丙只能同去或同不去，则不同的选派方案共有（　　）种．

阅读理解

It was a method favoured by the inventor Thomas Edison and the artist Salvador Dali. Waking from a nap exactly at the point before deep sleep in an effort to inspire creativity.

Edison held a metal ball in his hand so that if he nodded off he would drop it and the sound would wake him. For Dali, it was a key landing on a plate. Now scientists have found that they might have been onto something.

Researchers at the Paris Brain Institute studied people's ability to find a hidden rule in a maths puzzle.

Identifying the trick would make solving the problem far simpler but to do so required thinking creatively. The scientists found that participants who had been woken just before falling into a deep sleep, using a technique like that used by Edison and Dali, were more likely to find the shortcut.

This "twilight zone" is known as non-rapid eye movement sleep stage 1, or N1. Scientists described it like an exaggerated form of mind-wandering, where dream-like thoughts fill the mind. It is thought that as people start to disengage (脱离) from their environment they can "freely watch their minds wander, while maintaining their ability to identify creative sparks (火花)".

For the study 103 people were given a maths problem to solve. To reach the final answer they had to apply the rules step by step but, unknown to them, a "hidden rule" would allow them to bypass most of the steps and get to the solution much more quickly. The results showed that 83 percent of those in the N1 group had found the shortcut, compared with 31 percent in the group who were awake and 14 percent of those in a deep sleep.

Researchers conclude that the brain activity common to the twilight zone between sleep and wakefulness set off creative sparks. "Although the neural mechanisms (神经机制) involved are not yet known, our findings suggest that there is a creative sweet spot within the twilight zone, " said Dr Thomas

Andrillon, co-author of the study.

研制出脊髓灰质炎疫苗的我国科学家顾方舟，曾将疫苗接种到自己体内进行试验。从预防传染病流行的角度分析，接种疫苗属于（   ）

气体的制备是科学实验基本技能之一．现用如图所示装置制取初中科学中常见的气体．

听录音，选出你所听到的单词或短语。

-- _______ on the desk?

-- It's an English book.

在《月相变化》一课的学习前，李晓同学按老师的要求，从5月17日起进行了月相观察，记录如下：

公历	5月17日	5月18日	5月19日	5月20日	5月21日	5月22日	5月23日
月出时间	18：30	19：34	20：34	21：38	22：15	22：56	（不填）
月相

读“世界气候类型分布图”，回答问题。

用△标出9的因数，用○标出18的因数。

既是9的因数，又是18的因数：（       ）

近年来，许多地方政府“晒”出了权力运行流程图，明确规定行使权力的条件、承办岗位、办理时限、监督制约环节等，方便群众“按图索骥”。这一做法的积极影响是（    ）

科学的研究方法是取得成功的关键，假说—演绎法和类比推理是科学研究中常用的方法，人类在探索基因神秘踪迹的历程中，进行了如下研究：

①1866年孟德尔的豌豆杂交实验：提出了生物的性状由遗传因子（基因）控制

②1903年萨顿研究蝗虫的精子和卵细胞的形成过程，提出假说：基因在染色体上

③1910年摩尔根进行果蝇杂交实验：找到基因在染色体上的实验证据

他们在研究的过程中所使用的科学研究方法依次为（   ）