下列说法正确的是（　　）

已知元素R的某种同位素的氯化物RCl_x为离子化合物，其阳离子所含中子数为y，核外电子数为z，则该同位素的符号为（   ）

According to Carla, they should reach their (目的地) by about mid-afternoon.

氯元素在自然界有³⁵Cl和³⁷Cl两种同位素，在计算式34.969×75.77%+36.966×24.23%=35.453中（　　）

生态农业涉及农家肥料的综合利用．某种肥料经发酵得到一种含有甲烷、二氧化碳、氮气的混合气体8.96L（标准状况）．该气体通过盛有红色CuO粉末的硬质玻璃管，发生的反应为：CH₄+4CuO CO₂↑+2H₂O↑+4Cu．当甲烷完全反应后，硬质玻璃管的质量减轻了4.8g．将反应后气体通入2L0．1mol/L的澄清Ca（OH）₂溶液，充分吸收，生成沉淀10g．求：

若集合 中的三个元素可构成某个三角形的三条边长，则此三角形一定不是（    ）

在 中，若 ，则 的形状为（    ）

已知锐角三角形的三边长分别为 ,则 的取值范围为.

下列各组句子中，加点词语的意义和用法相同的一组是（   ）

语篇填空

    In general, rules vary for every team although a woman who wants to try out for  of the NBA cheerleading teams must:

    Be able to dance: Almost all of the NBA cheerleaders are (dance). It goes without saying that in order to be an NBA cheerleader, you have to be able to dance since the (major) of your job is to perform dance routines.  

    Be 21 years of age: There are (general) no height or weight requirements, but you must be 21 in order to try out for an NBA cheerleading team.  

    Be fit and in shape: The NBA does not require its cheerleaders to maintain a certain weight or (high). However, you have to be  shape to dance through hours of auditions if you try out for an NBA cheerleading team.  

    Have a flexible schedule: The NBA cheerleaders make appearances and do promotional events in addition to (cheer) for games.  

    The auditions for almost all of the NBA teams (post) in public places so that people can watch them. On each team's website there is a spot for you to vote  the dancer you'd like to see. No doubt, the NBA cheerleading takes fan support to  entirely new level.

短文改错。
假如英语客商老师要求同桌之间交换修改作文,请你修改你同桌的以下作文。文中共有10处语言错误,每句中最多有两处；每处错误仅涉及一个单词的增加,删除或修改。
增加：在缺词处加一个漏字符合(^),并在其下面写出该加的词。
删除：把多余的词用斜线(\)划掉。
修改：在错的词下划—横线,并在该下面写出修改改后的词。
注意：1）.每处错误及其修改均仅限一词；
2）.只允许修改10处,多者（从第11处起）不计分。
    My friend Nick told me story about his experience back in the US, that is very interesting. One day he was having a yard sale and the old man living next door come by to help. As the old man looked over the things on the yard that was to be sold, he stopped at a box of golden balls for Christmas trees. On the box was a card say: “25 cents each.” “You will never sell these for that much,” he told Nick. Convincing, Nick has brought the price up to 10 cents a piece. Without a moment's delay, my neighbor picked up the box but announced: “I will take them.”

The little boy,(disappoint) at the exam results, thought something by himself without saying anything.

阅读下面这首唐诗，完成下面小题。

赴巴南书情寄故人

刘长卿

南过三湘去，巴人此路偏。

谪居秋瘴里，归处夕阳边。

直道天何在，愁容镜亦怜。

裁书欲谁诉，无泪可潸然。

注：诗人祖籍宣城，居洛阳。中年始入仕，为人刚直，被诬入狱，遇大赦后不久，再谪巴南尉。

阅读理解

    Barack Obama was born on August 4, 1961 in Honolulu, Hawaii. His father came to America from Kenya, which is a country in Africa. His parents, Ann and Barack, met when they were students at the University of Hawaii. Since Barack had the same name as his father, young Barack went by the nickname “Barry”.

    In 1979, after he finished high school, Barry went to Occidental College in Los Angeles, California. There, he started to learn about his African roots and decided to use his African name, Barack. After two years in L.A., he went to Columbia University in New York City to study politics.

    After college, he moved to Chicago, Illinois, where he worked to help poor people in his city. He traveled to Africa to meet his grandmother and cousins for the first time. He went back many times over the years to visit with his family and learn about where he came from. At work, he met a lawyer named Michelle Robinson. They worked together in a big law firm. Then he left Chicago to go to Harvard Law School in Cambridge, Massachusetts. He did very well in law school.

    After he was done with school, Barack moved back to Chicago and in 1992 he married Michelle. He worked as a lawyer, devoted to helping poor people for free who had been treated unfairly. He worked hard to get the people he helped to vote.

    He made many people believe that their votes were important, and helped them feel like they could make a difference.

完形填空

    Sarah grew up on a fishing boat. Her father,1to make enough money to buy a house, had 2 her within their only small boat since his wife died.

    One morning, Sarah saw a 3above the sea, which was close to them, and the boat began to rock as waves grew. 4 a mountain of clouds approaching from the south, she rushed below deck(甲板), 'Dad, 5.

    "What?" her drunken father asked 6.

    "Dad, a big storm is coming. We need to get out of here. "She grabbed his shoulders and 7 him. He got angry, shouting, "What are you doing?"

    "Dad, we have to 8the boat. There's a big storm coming. "

    Her father 9her at last. He walked to the deck, saw the10and fired up the engine.

    "Dad, what are you doing?"

    "Sarah, 11we stay here, we will die. We need to get out of the sea. We must ride the waves; that's our only 12."

    Their boat headed into the storm 13. Above them were black clouds and in front of them were dark waves. It was so 14.

    Hours passed. The dark day turned into darkness totally. They held each other for 15, but the experienced fisherman needed no 16 because he had fought many such battles.

    Eventually, the waves 17 and the sky brightened. Sarah was 18 and hugged her father, "You did it, Dad."

    They sailed back into the port. Other boats had been destroyed. Their boat was the only one to 19 the storm. Sarah hugged her father again. "Dad, you made it. You 20 us."

    "No, Sarah," he held her by his arms, "we did it together."

将足量的MnO₂与含14.6gHCl的浓盐酸共热制取氯气，可制得Cl₂的质量是（   ）

在ΔABC中，若 ，则ΔABC是（   ）

我会把一半的假期时间用来练习英语。(spend)

¹⁴C常用于测定生物遗骸的年份．下列说法中正确的是（   ）

甲、乙、丙、丁四个烧杯内分别放人0.1mol的钠、氧化钠、过氧化钠和氢氧化钠，然后各加入100mL水，搅拌，使固体完全溶解，则甲、乙、丙、丁的质量分数大小的顺序是（   ）