下列关于营养级的叙述，正确的是（    ）

A. 营养级的位置越高，归属于这个营养级的能量通常越多

B. 自然生态系统中的所有绿色植物都属于生产者营养级

C. 营养级是指处于食物链同一环节上同种生物的总和

D. 食物链中的各营养级之间能量传递效率是相同的

岳桦林带是长白山海拔最高的森林带。岳桦林带气候寒冷，生长季短，只有其下部的岳桦才结实（种子）。岳桦结实的海拔上限称为岳桦结实线，岳桦林分布上限即长白山林线。监测表明，20世纪90年代以来，长白山北坡气候持续变暖，岳桦结实线基本稳定；林线的海拔快速提升了70~80米，但近年趋于稳定。据此完成下面小题。

9. 目前，长白山北坡林线附近的岳桦多为（   ）

A. 幼树                                       B. 中龄结实树

C. 老树                                       D. 各树龄组混生

10. 推测20世纪90年代以来，长白山北坡岳桦林带（   ）

A. 冬季升温幅度小，生长季稳定                 B. 冬季升温幅度大，生长季延长

C. 冬季升温幅度大，生长季稳定                 D. 冬季升温幅度小，生长季延长

11. 在气候变暖背景下，长白山北坡林线近年却趋于稳定，原因可能是（   ）

A. 降水稳定                                   B. 水土流失量稳定

C. 土壤肥力稳定                               D. 岳桦结实线稳定

Even if you’ve never been to Phoenix in Arizona, you probably know this about the place: its terrible _____. From June to September, the temperature can easily climb up to an unbearable point. But that doesn’t _____ hikers from attempting the 1.3-mile hard walk to the top of the city’s famous Camelback Mountain. Signs _____ that the trail is extremely difficult. If you continue, a posted checklist suggests at least a liter of water per person. And _____you’re still not stopped, another _____ farther up declares: “If you’re halfway through your water, turn around!”
_____ many people hardly pay any attention to the warnings. Fortunately, Scott Cullymore does. When he’s not _____ his carpet-cleaning company nearby, the 53-year-old Cullymore can be found hiking up and down Camelback a couple of times a day, _____ cold bottles of water to _____ hikers. He has helped so many hikers that he has _____ a heavenly nickname: the Water Angel. “I’d like a more manly name, but, you know,” he joked. Cullymore was on Camelback Mountain one day in 2015 _____ a British tourist died after being lost for nearly six hours in the hot July. That experience _____ him to start helping people _____ caught by the unforgiving version of Mother Nature. “They lack deep understanding of the mountain, and they feel too _____ of what they can do, and so they get themselves in trouble,” he told the Arizona Republic. If a hiker has a flushed face and is not sweating anymore, Cullymore says that he _____ his backpack, pulls out a frosty bottle, and hands it to the person. “It’s _____ that we’re safe in the middle of the city. You can die up here, and no one would know.” One hiker who enjoyed the _____ of offered water agrees. “You think you know the hot weather, but then you get out here in the desert and it _____ you like a blanket. You have no way to get out,” said Austin Hill, who was hiking with a high school friend. They were _____, he said, pointing to Cullymore. “We ran into this Good Samaritan(乐善好施者) here.” And with that, the Water Angel goes _____ another hiker in trouble.
【1】A. altitude B. heat C. drought D. surroundings
【2】A. refuse B. separate C. relieve D. discourage
【3】A. warn B. remind C. advise D. recommend
【4】A. as B. if C. unless D. until
【5】A. hiker B. guide C. sign D. tourist
【6】A. However B. Therefore C. Instead D. Moreover
【7】A. starting B. making C. running D. setting
【8】A. unpacking B. distributing C. collecting D. purchasing
【9】A. scared B. pleased C. exhausted D. thrilled
【10】A. earned B. created C. presented D. gathered
【11】A. before B. after C. when D. while
【12】A. required B. indicated C. disturbed D. inspired
【13】A. unchangeably B. unconsciously C. unreasonably D. unnaturally
【14】A. curious B. satisfied C. anxious D. confident
【15】A. carries out B. lifts up C. sets aside D. reaches into
【16】A. misleading B. mistaken C. unbelievable D. unexpected
【17】A. fun B. benefit C. convenience D. popularity
【18】A. surrounds B. treats C. provides D. strikes
【19】A. faithful B. considerate C. experienced D. lucky
【20】A. in need of B. in search of C. in place of D. in charge of

1. TrueCar.com
Top dealers compete for your business by offering lower prices. TrueCar spends a lot of money and resources on making sure the entire car renting experience is simple and straightforward. If you’re in the market for a new car, give this site a try first.
TrueCar’s network checks many of the prices in your area and gets you the best price for the car you’re looking for.
2. Carvoy.com
It offers more control by allowing you to “build your car” and select your rental plan. The “build your car” option is one of the better options for those looking to add on features to their car. If you’re looking for cars with options like a sunroof or navigation (导航), it’s Carvoy that makes it very easy to get started with the process.
3. CarsDirect.com
They have a large collection of new and used cars, and also provide resources for car comparisons. In the business for many years, they are one of the first online car outlets. They have a staff that can usually help you if you give them a call. Their phone support is very good and they are mostly located in the United States.
4. CarRent.com
It delivers your rental car to the door, which is actually a huge selling point. Many people don’t like to go to a dealership or even drive somewhere to pick up a car. Imagine renting a car and having it delivered right to your doorstep, no driving necessary!
5. CostcoAuto.com
It offers member-only savings, many car selections and an easy sign-up process. The deals through Costco are great and unique. Many times they have deals with General Motors cars like Chevrolet. There are a lot of deals to be done, but the one thing that Costco does not do is negotiate the price.
【1】What’s the selling point of TrueCar.com?
A. Its most reasonable prices for cars.
B. The diversity of its used cars.
C. Its delivery service to your door.
D. The special offers to its members.
【2】What is the special service that Carvoy.com provides?
A. You can have other functions added to your car.
B. You can rent a car more easily than elsewhere.
C. You can design the whole car by yourself.
D. You can have better operation over your car.
【3】If you are a good bargainer, it’s wise to avoid dealing with _______.
A. CarsDirect.com B. Carvoy.com
C. CarRent.com D. CostcoAuto.com

(2019·天津高考)Understanding history is vital to understanding ourselves as ________ people and as ________ nation.

化学与科技、社会、生产密切相关，下列说法错误的是
A. 我国出土的青铜礼器司母戊鼎是铜和铁的合金
B. 高纯硅具有良好的半导体性能，可用于制光电池
C. 港珠澳大桥钢筋表面的环氧树脂涂层属于合成高分子材料
D. 火箭推进剂使用煤油-液氧比偏二甲肼-四氧化二氮的环境污染小

若用较低浓度的生长素处理未授粉的番茄雌蕊柱头，可能产生的结果是（　　）
A. 促进番茄果实细胞中快速合成大量乙烯 B. 促进番茄雌蕊子房逐渐发育成无子果实
C. 使番茄果肉细胞的染色体数目发生改变 D. 诱发减数分裂中的同源染色体联会紊乱

伊塞克湖（下图）湖面平均海拔约1608米，面积6300多平方千米，是世界最深的高山大湖，湖水清澈澄碧，终年不冻。读图，回答下列各题。

【1】关于伊塞克湖的叙述，正确的是
A. 伊塞克湖东岸降雪多于西岸 B. 伊塞克湖水补给主要来源于降水
C. 伊塞克湖水位季节变化小 D. 伊塞克湖春季水位最高
【2】伊塞克湖终年不冻的主要原因是
①纬度低 ②山地环绕 ③湖水盐度高 ④湖泊水深量大
A. ①②③ B. ①③④ C. ②③④ D. ①②④

假设你是遂宁某中学高三学生李华，你的美国朋友Jim想了解你校学生课外阅读情况。请你回一封邮件，内容包括：
1．你校学生课外阅读现状；
2．原因分析
3．你的看法。
注意：1．词数120；
2．开头和结尾已给出，不计入总词数。
提示词：课外阅读 extracurricular reading
Dear Jim，
In your last letter, you told me that you wanted to learn something about the extracurricular reading in our school.
_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Yours，
Li Hua

李斯特 1837年访问里昂时写的一封信中说：“到里昂就陷入一种骇人听闻的苦难和令人难以忍受的贫国环境之中，使我非常悲痛，深感世道不公。看他们徒劳地与贫困搏斗，心灵与肉体一起断送于贫困之中，这该是多么令人难以忍受啊！他们甚至连遮体的破衣烂裳都没有，却用自己的双手制出名贵的织品，织成华丽的衣料，供娇生惯养的富人穿着无所事事。”材料反映的社会问题出现的历史背景是

A ． 工业革命导致阶级分化 B ． 机器使用导致手工业者破产

C ． 资产阶级革命后的社会动荡 D ． 大量使用童工到致工资水平降低

将正整数分解成两个正整数的乘积有，，三种，其中是这三种分解中两数差的绝对值最小的，我们称为的最佳分解.当且是正整数的最佳分解时我们定义函数，例如.则的值为___________，数列的前项的和为____________.

公元前5世纪的希腊人对民主政治是毁誉参半的，总体上以肯定为主，认为是一种理想政体，但从公元前5世纪末以来，随着雅典在伯罗奔尼撒战争中惨败，批评逐渐成为主流，被认为是一种暴民政治。这一变化反映了
A. 直接民主的弊端随时间日益凸显
B. 早期民主政治推动了希腊繁荣
C. 雅典战争失利导致民主政治衰落
D. 后期民主政治日趋走向了专断

碳的化合物在生产、生活中有着重要的作用。
（1）已知：2CO(g)+O2(g) 2CO2(g) △H1=－566kJ·molˉ1
H2O(g)+CO(g) H2(g)+CO2(g) △H2=－41kJ·molˉ1
CO(g)+2H2(g) CH3 OH(g) △H3=－107 kJ. molˉ1
则CH3OH(g)+O2(g) CO2(g)+2H2O(g) △H=___________kJ·molˉ1，增大压强，CH3OH(g)的转化率___________(填“增大”“减小”或“不变”，下同)，升高温度，CH3OH(g)的转化率___________。
（2）T℃时，向容积均为2L的A、B两个密闭容器中均通入4.0 mol CO2和6.8molH2，发生反应：CO2(g)+3H2(g) CH3OH(g)+H2O(g) △H=—50kJ·molˉ1。A容器中的反应在恒温、恒容条件下进行；B容器中的反应在恒温、恒压条件下进行，测得A容器中CO2的转化率[α(CO2)]随时间的变化如图所示。

①在0~5min内A容器中v(CH3OH)=_______；该温度下上述反应的平衡常数K=_______(保留两位有效数字)。
②反应开始至平衡的过程中，A、B两容器中CO2的消耗速率的大小关系为v(A) ________(填“>”“<”或“=”)v(B)。
③下列各项指标能表明A容器中反应的v正>v逆的是___(填标号)
a.体系内的压强增大
b.气体的平均相对分子质量增大
c.断裂H－H键的数目是形成C－O键数目的2倍
d.v逆(CO2)=v正(H2)

在物理学发展过程中，观测、实验、假说和逻辑推理等方法都起到了重要作用。下列叙述符合历史事实的是（　　）
A. 奥斯特在实验中观察到电流的磁效应，该效应揭示了电与磁之间存在必然的联系
B. 安培在实验中观察到导线静止，通有恒定电流，在其附近的固定导线线圈中，会出现感应电流
C. 库仑发现通电导线在磁场中会受到力的作用
D. 法拉第在分析了许多实验事实后提出，感应电流应具有这样的方向，即感应电流的磁场总要阻碍引起感应电流的磁通量的变化

甲状腺功能减退的致病原因有：缺碘、甲状腺病变、下丘脑病变或垂体病变。为探究甲、乙两只甲状腺功能减退小鼠的致病原因，科研人员测定了甲、乙及健康小鼠体内促甲状腺激素释放激素(TRH)、促甲状腺激素(TSH)和甲状腺激素(TH)的含量，结果见下表。下列叙述错误的是

	健康小鼠	甲	乙
TRH含量	正常	偏高	偏高
TSH含量	正常	偏低	偏高
TH含量	正常	偏低	偏低

A. 甲状腺激素的分泌过程存在分级调节和反馈调节
B. 甲的致病原因是垂体病变，补充垂体提取液后症状会缓解
C. 欲确定乙是否发生甲状腺病变，可补充碘后测定TH的含量
D. 甲、乙两小鼠表现为厌食、行动迟缓，体温略高于正常小鼠

敦煌具注历日中，漏刻标注呈现的是昼夜百刻制。漏是指计时用的漏壶，刻是指划分一天的时间单位，它通过漏壶的浮箭来计量一昼夜的时刻。漏箭浮在水面上，上面有刻度，随着水位变化，可以指示时间的流逝。漏箭上刻度固定，不能伸缩，需要经常更换，称为“漏刻改箭”。下图为漏刻示意图。
据此完成下列各题。

【1】古人“漏刻改箭”可能是因为
A. 昼夜不断更替 B. 太阳高度变化
C. 昼夜长短变化 D. 季节冷暖更替
【2】若敦煌具注历日显示“昼六十夜四十”，则该日敦煌日落时的地方时是
A. 17：00 B. 18：00
C. 18：40 D. 19：12

如图所示，“冰雪游乐场”滑道O点的左边为水平滑道，右边为高度h = 3.2m的曲面滑道，左右两边的滑道在O点平滑连接。小孩乘坐冰车由静止开始从滑道顶端出发，经过O点后与处于静止状态的家长所坐的冰车发生碰撞，碰撞后小孩及其冰车恰好停止运动。已知小孩和冰车的总质量m = 30kg，家长和冰车的总质量为M = 60kg，人与冰车均可视为质点，不计一切摩擦阻力，取重力加速度g = 10 m/s2，求：

(1)小孩乘坐冰车经过O点时的速度大小；
(2)碰撞后家长和冰车共同运动的速度大小；
(3)碰撞过程中小孩和家长（包括各自冰车）组成的系统损失的机械能。

当北京迎来新年第一缕阳光时，我国某地还在黑夜中，该地最不可能位于北京的
（ ）
A. 东南方向 B. 东北方向
C. 西北方向 D. 西南方向

将多项式分解因式得，为常数，若，则（ ）
A. -2 B. -1 C. 1 D. 2

设，则“”是“复数为纯虚数”的（ ）
A. 充分不必要条件
B. 必要不充分条件
C. 充分必要条件
D. 既不充分也不必要条件