题干

将废弃农田改造成芦苇湿地,通过生物降解、吸收,可以有效解决生活污水和农业生产对水源造成的污染问题.下列说法错误的是(  )

 

A:芦苇湿地构成了一个在物质和能量上自给自足的生态系统

B:芦苇湿地不同地段物种组成上的差异是群落水平结构的体现

C:从废弃农田到芦苇湿地的变化属于次生演替,该过程体现了人类对群落演替的影响

D:芦苇湿地中生物种类多样,通过负反馈调节维持其结构和功能的相对稳定

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A

同类题1

根据短文理解,选择正确答案。

My Hero

    What does it mean to be a hero? I think a hero is someone who goes out of his way to make others happy. My hero is Mr. Wright, my chorus(合唱队) teacher.

    When I was 12 years old, my grandparents passed away. I was really close to them, and losing them was the hardest thing I've ever had to1through. I couldn't eat, sleep, or think; I felt like I couldn't even breathe. It was as if my whole world had fallen down from under me, and I2into this huge hole of depression(抑郁).

    3I was battling depression, I was determined to make my high school years the best of my life. It was difficult to be 4, but I had to try. I joined Women's Choir. Mr. Wright was the choral director and he was so funny that the first day, I just knew I had made the best5of my life. As the year progressed, I loved chorus more and more. I began to smile again and really enjoy 6.

    Then one day that all changed. My friends—or those that I thought were my friends—started talking about me behind my back. I was7 , and I sat by myself. Mr. Wright came over and asked what was wrong. The look in his eyes told me that I could8him. Trying hard to9 back tears, I told him the whole story.

    When I finished, he nodded and told me, “If you never learn anything from me, learn this: No one is worth 10 your joy.” What Mr. Wright said really11a chord (心弦) in my heart. He 12 cared about me and what was going on. I'll never be able to thank him enough, because he not only saved me but has13every day of it since. Any time I feel like giving 14, I remember Mr. Wright's words and push forward.

    I'm proud to say that I 15 my depression, and I'm now a senior. I'm still a16of chorus, and now I'm also in the best choir at my school.

Mr. Wright is a hero 17 everyone he meets. He cares about every single person who walks through his door, and he loves what he does more than any other teacher I've known. That's18  he deserves to be Educator of the Year. He deserves the19 not just this year but every year.

    I'm glad I had the opportunity to meet you, Mr. Wright. You are an 20teacher, and I hope you realize that. You're my hero.

同类题3

阅读理解

    When Carson Palmer, a professional American football player, hurt his arm a few years ago, he took a week off from throwing the football. But in his head, Palmer practiced every day. The following weekend, Palmer had the best game of his life.

    For more than a century, scientists have been trying to understand how this mental training works. In the 1930s, researchers proved by experiment that when you're imagining an action, your brain sends signals to your muscles(肌肉) which are too weak to tighten the muscles but might help train the body to perform. In other words, mental practice might create a pattern in your head, like an inner how-to guide for a particular skill.

    Sports psychologists have conducted hundreds of studies comparing imagined and physical practice for actions. On the whole, the research shows that mental training works. A 2012 study, for example, compared 32 amateur golfers who practiced hitting the balls to another 32 who merely held a golf club in their hands and visualized(想象)their swings. Under the same training rules, both groups improved their skills by getting the ball about 4 inches closer to the hole.

    Visualization has advantages over the real thing: You can do it anywhere, even when injured. It is safe-a major plus for high-risk performers such as gymnasts and surgeons. And you can practice for longer periods of time because you're not restricted by physical tiredness, That's not to say it's easy, we've had Olympic-level athletes sitting in our lab, visualizing the movements for two hours," says Tadhg Macintyre, a sports psychologist at the University of Limerick in Ireland. “When we're done, they're absolutely tired.”

    It doesn't work for everyone, though. "If you're a novice, the effect can be harmful,” warns Macintyre. If you're trying to visualize a free throw, and you don't even know the proper movement, then you're probably going to mentally practice the wrong skill.”