皮皮学，免费搜题
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【单选题】
振荡电路产生自激振荡的振幅条件是:反馈到放大器输入端的( )幅值必须等于或者大于放大器的原输入电压幅值。A.
电流
B.
电压
C.
电阻
D.
电容
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皮皮学刷刷变学霸
举一反三
【单选题】The two essential parts of a deal negotiation are ( ) .
A.
Enquiry and acceptance
B.
Offer and counter-offer
C.
Counter-offer and acceptance
D.
offer and acceptance
【单选题】________are two essential factors to form a contract.
A.
Enquiry and offer
B.
Offer and counter-offer
C.
Enquiry and acceptance
D.
Offer and acceptance
【简答题】外周免疫器官包括____________、____________和黏膜相关淋巴组织。
【多选题】What are the two essential components of scientific research?
A.
Hypothesis
B.
Concepts
C.
Observation
D.
Theory
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