通过调节运算放大器的负反馈电阻大小 可以改变放大电路的增益
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运放接入负反馈可以改善电路性能,接入正反馈可以产生自激振荡
A. 对
B. 错
Section A21.the investigation, the committee published the report on the cause of the accident.
A)Completed
B)Completing
C)Having completed
D) To have completed
22.The report shows that over half of the women are suffering_________second-hand smoke at theworkplace.
A)in
B)for
C)on
D)from
23. Our goal is to fulfill the needs of our clients, __________challenging they may be.
A)however
B)whenever
C)wherever
D)whatever