问题
选择题
下图中曲线表示了某生态系统中三个不同种群的数量变化情况，已知种群C为自养生物，下列说法不正确的是
A．此三种生物构成的简单食物链可表示为C→B→A
B．种群B在5—7年间个体数下降是由于A的增加和C的减少所致
C．B和A的存在能加快该生态系统的物质循环
D．一定自然区域内，A、B、C三个种群中全部的生物构成生物群落
答案
答案：D
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下图中曲线表示了某生态系统中三个不同种群的数量变化情况，已知种群C为自养生物，下列说法不正确的是
A．此三种生物构成的简单食物链可表示为C→B→A
B．种群B在5—7年间个体数下降是由于A的增加和C的减少所致
C．B和A的存在能加快该生态系统的物质循环
D．一定自然区域内，A、B、C三个种群中全部的生物构成生物群落
答案：D
| 根据对话内容，从方框内选择恰当的句子,并将其字母标号填入对话相应的空白处，使对话完整， 合乎情景。（有两个多余选项) | |
| Jack: Was the concert good? Sadie: (1) ___________________ Jack: Why are you angry then? (2) ___________________ Sadie: Well, after the concert I waited outside the theatre-in the rain. I wanted their autographs. Jack: Did you see them? Sadie: (3) ___________________ Jack: Did they talk to you? Sadie: No, they didn't. They didn't wave. They didn't smile. They didn't say hello. (4) ___________________ They just jumped into a big, black car and then disappeared. Jack: (5) ___________________ Sadie: Yes. But that was yesterday.
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