在一定条件下，某化合物X受热分解：2X=A↑+2B↑+4C↑，测得反应后生成的混合气体对H₂的相对密度为11.43．则在相同

条件下，X的相对分子质量是（   ）

阅读下面的文字，根据要求写作｡

我们，相遇或相处，相知或相守……总有一些经历触动着我们的心灵，总有一些感受难以忘怀｡

请以“我们之间”为题，写一篇记叙文｡

要求：①内容充实，感情真挚；②综合运用记叙、描写和抒情等多种表达方式；③不要套作，不得抄袭；④不得泄露个人信息；⑤不少于800字｡

It was the boy, rather than his brothers, that _________ for what they had done.

某固体A在一定条件下加热分解，产物全是气体，A的分解反应为：2A B↑+2C↑+2D↑，现测得分解产生的混合气体对氢气的相对密度为d，则A的相对分子质量为（　　）

重水（D₂O）是重要的核工业原料，下列说法错误的是（   ）

Americans eat ______ vegetables per person today as they did in 1990.

硫铁矿又称黄铁矿，是生产硫酸的原料，其主要成分为FeS₂.850℃～900℃时，硫铁矿在氧气中煅烧，可能发生下列反应（假设空气中的N₂和O₂体积比为4：1）

①3FeS₂+8O₂→Fe₃O₄+6SO₂         ②4FeS₂+11O₂→2Fe₂O₃+8SO₂

In autumn, the leaves (由绿变黄).(change)

已知 中， 且 ，则 是（   ）

某温度时，浓度都是 1 mol·L-1 的两种气体 X₂ 和 Y ₂ ，在密闭容器中发生可逆反应生成气体 Z，充分反应后 X ₂的浓度为 0.4 mol·L^-1 ，Y₂ 的浓度为 0.6mol·L^-1 ，生成的 Z 的浓度为 0.4 mol·L ^-1 ，则该反应的化学方程式(Z 用 X、Y 表示)是（ ）

按要求填空

Don't worry. He's now fully _______ from the operation.

The boy wanted to ride his bicycle in the street, but his mother told him________.

阅读理解

    Surviving Hurricane Sandy(飓风桑迪)

    Natalie Doan, 14, has always felt lucky to live in Rockaway, New York. Living just a few blocks from the beach, Natalie can see the ocean and hear the waves from her house. "It's the ocean that makes Rockaway so special, "she says.

    On October 29, 2012, that ocean turned fierce. That night, Hurricane Sandy attacked the East Coast, and Rockaway was hit especially hard. Fortunately, Natalie's family escaped to Brooklyn shortly before the city's bridges closed.

    When they returned to Rockaway the next day, they found their neighborhood in ruins. Many of Natalie's friends had lost their homes and were living far away. All around her, people were suffering, especially the elderly. Natalie's school was so damaged that she had to temporarily attend a school in Brooklyn.

    In the following few days, the men and women helping Rockaway recover inspired Natalie. Volunteers came with carloads of donated clothing and toys. Neighbors devoted their spare time to helping others rebuild. Teenagers climbed dozens of flights of stairs to deliver water and food to elderly people trapped in powerless high-rise buildings.

    "My mom tells me that I can't control what happens to me, "Natalie says, "but I can always choose how I deal with it."

    Natalie's choice was to help.

    She created a website page, matching survivors in need with donors who wanted to help. Natalie posted information about a boy named Patrick, who lost his baseball card collection when his house burned down. Within days, Patrick's collection was replaced.

    In the coming months, her website page helped lots of kids: Christopher, who received a new basketball; Charlie, who got a new keyboard. Natalie also worked with other organizations to bring much-needed supplies to Rockaway. Her efforts made her a famous person. Last April, she was invited to the White House and honored as a Hurricane Sandy Champion of Change.

    Today, the scars(创痕) of destruction are still seen in Rockaway, but hope is in the air. The streets are clear, and many homes have been rebuilt. "I can't imagine living anywhere but Rockaway, "Natalie declares. "My neighborhood will be back, even stronger than before. "

在△ABC中，已知 ，则△ABC为三角形．

下列粒子的结构示意图中，表示金属元素的原子的是（　　）

在农业上常用于辐射育种。该原子的质子数是（    ）

镁和铝分别与等浓度、等体积的过量稀硫酸反应，产生气体的体积（V）与时间（t）关系如图．反应中镁和铝的（   ）

在△ABC中，角A、B、C所对的边分别为a、b、c．若a=2bcosC，则△ABC的形状为 

选择适当的短语并用其正确形式填空

return to     wait...for      be able to      wave to    separate from     fly to     because of