20世纪30年代，苏联私人土地虽然只占总耕地面积的3%~5%，却生产了25%~30%的苏联农产农产品。这反映了（  ）

科学发展观要求在经济建设中保护生态环境，则下列做法不正确的是（   ）

某兴趣小组为测定实验室中一瓶久置的过氧化氢溶液中溶质的质量分数，实验测得相关数据如下图所示：

网络销售已经成为一种热门的销售方式，为了减少农产品的库存，某市市长亲自在网络平台上进行直播销售板栗，为提高大家购买的积极性，直播时，板栗公司每天拿出2000元现金，作为红包发给购买者.已知该板栗的成本价格为6元/ ， 每日销售量与销售单价x（元/）满足关系式：.经销售发现，销售单价不低于成本价且不高于30元/.设板栗公司销售该板栗的日获利为w（元）.

若关于x的方程mx²﹣mx+2=0有两个相等的实数根，则m的值为（   ）

使苏联有农业国变为工业国的标志是（  ）

It's common that some people prefer to sell their old houses (buy) new ones.

第一次世界大战削弱了帝国主义的殖民力量，进一步促进了殖民地半殖民地国家的民族觉醒。下列事件体现了这一论述的是（    ）

Wu Wei, a young artist, has received high ____________from the art community for this sculpture.

下列划线字注音完全正确的一项是（    ）

(the work，finish，next week)
.

阅读理解

    Do you have the experience of taking music lessons against your wishes? Perhaps you have complained about it because you thought it took you much playtime. But now you'd better thank your parents for their time and money spent on your musical training. A recent study suggests music lessons can make children have better memories than their peers （同龄人）.

    The Canadian study showed that after one year of musical training, children did better on a memory test than those who didn't take music lessons.

    The researchers made the children aged between 4and 6into two groups﹣one group of children took music lessons outside school, and the other didn't take any musical training. In one year, they took four tests in different times. The results showed brain （大脑）development changes at least every four months.

    The children taking music lessons not only did better in musical listening but also made faster progress in other ways, such as reading, writing, Maths and IQ.

    People say music is the good medicine for a broken heart. Now it seems music can also help us to improve our memories. We are sure to find more and more in the wonderful world of music.

阅读理解

    Many people have great difficulty in saying goodbye. But from goodbye moments, we can always learn something.

    Once, I overheard(无意中听到) a father and daughter in their goodbye moment. The father said, "I love you, I wish you enough." The daughter answered, "Daddy, our life together has been more than enough. Your love is all that I need. I wish you enough, too, Daddy."

    They kissed and she left …

    The father walked over towards me. I could see he wanted and needed a cry. He came over to me and asked, "Did you ever say a forever goodbye to someone?" Before I could answer, he went on, "I am old and she lives much too far away. I know her next trip back would be for my funeral(葬礼)."

    "When you were saying goodbye I heard you say, 'I wish you enough.' May I ask what that means?"

    He began to smile, "It's a wish that has come down from my great-great-grandparents. And my parents used to say it to me."

    He stopped for a moment and looked up as if trying to remember it. He smiled even more.

    "When we said 'I wish you enough,' we were wanting the other person to have a life full of enough good things."

    Then, turning towards me, he shared the following "wish" from his heart.

    I wish you enough sun to keep you bright.

    I wish you enough rain to appreciate the sun more.

    I wish you enough happiness to keep you alive.

    I wish you enough pain so that the smallest joys in life appear much bigger.

    I wish enough hellos to get you through the final goodbye.

    My friends, I wish you enough.

如图所示，第二届亚洲青年运动会前夕，主办方通过古老的钻木取火方式，在几分钟内就取得了火种，并点燃火炬。请你用学过的物理知识说明钻木取火的原理。

实验室用过氧化氢制取氧气，若实验中忘记加入二氧化锰，其结果是（　　）

氦气可以填充飞艇，“氦”的元素符号是（　　）

用图中所示的装置探究杠杆的平衡条件， 通过正确的实验操作， 得到下表中的数据。

实验次数	动力F1/N	动力臂l1/m	阻力F2/N	阻力臂l2/m
1	3.0	0.20	2.0	0.30
2	2.0	0.15	1.5
3	1.5	0.20	1.0	0.30
……	……	……	……	……

同种材料制成的长度相等的甲、乙导体串联在电路中，若甲导体两端的电压大于乙导体两端的电压，则关于甲、乙的横截面积S_甲、S_乙大小，下列判断正确的是（   ）

如图所示的三种场景中，拉力F₁、F₂、F₃大小相等，在拉力的作用下物体移动的距离也相等．若拉力所做的功分别记为W₁、W₂、W₃ ， 下列关于它们大小关系的判断中正确的是（   ）

下列微粒符号中，对“2”的含义理解正确的是（   ）