What does the author mean by "undisputed"(line 4, para. 1)？
A. Disproved.
B. Debated.
C. Unquestioned.
D. Underrated.
What has been generally accepted as the reason for adolescence？
A. To allow humans to become sexually mature.
B. To give us an extended childhood during which to learn.
C. To allow us to grow to our relatively large size, compared with other primates.
D. So that parents will take more care of their children.
把输出电压短路后，如果反馈不存在了，则此反馈是电压反馈。()
在输入电压从足够低逐渐增大到足够高的过程中，电平比较器和滞回比较器的输出电压均只跃变一次。()
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