题干

针、阔叶林混交,对马尾松和山毛榉的存有量逐年统计,并把马尾松存有量与山毛榉存有量的比值记作Y值,作曲线如右图,下列有关叙述中不正确的是(   )

A:马尾松与山毛榉存在竞争关系

B:a、d年份的优势种分别是山毛榉和马尾松

C:根据曲线能推论出:混交林中的山毛榉比马尾松更适应当地的环境,

D:混交后的混交林要比人工单纯林更能抵抗虫害

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答案(点此获取答案解析)

B

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    Five years ago, when I taught art at a school in Seattle, I used Tinkertoys as a test at the beginning of a term to find out something about my students. I put a small set of Tinkertoys in front of each student, and said: “Make something out of the Tinkertoys. You have 45 minutes today - and 45minutes each day for the rest of the week.”

    A few students hesitated to start. They waited to see the rest of the class would do. Several others checked the instructions and made something according to one of the model plans provided. Another group built something out of their own imaginations.

    Once I had a boy who worked experimentally with Tinkertoys in his free time. His constructions filled a shelf in the art classroom and a good part of his bedroom at home. I was delighted at the presence of such a student. Here was an exceptionally creative mind at work. His presence meant that I had an unexpected teaching assistant in class whose creativity would infect(感染) other students.

    Encouraging this kind of thinking has a downside. I ran the risk of losing those students who had a different style of thinking. Without fail one would declare, “But I'm just not creative.”

    “Do you dream at night when you're asleep?”

    “Oh, sure.”

    “So tell me one of your most interesting dreams.” The student would tell something wildly imaginative. Flying in the sky or in a time machine or growing three heads. “That's pretty creative. Who does that for you?”

    “Nobody. I do it.”

    “Really-at night, when you're asleep?”

    “Sure.”

    “Try doing it in the daytime, in class, okay?”