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【单选题】
—What have you been busy with these days? —I ______ that the speech contest has been brought forward, so I ______ for it.A.
was informed; have been preparing
B.
have informed; am preparing
C.
informed; have prepared
D.
was informed; prepared
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反馈参考答案：
举一反三
【多选题】如图题 6.1 所示,对电路的正确描述是( )。
A.
这是共集电极放大电路， R e 是直流负反馈，是用来稳定静态工作点。
B.
电阻 R b1 、 R b2 、 R e 是交流并联，闭环增益是闭环互阻增益。
C.
C 3 引入了交流负反馈，构成的是电压并联负反馈。
D.
C 3 引入了交流负反馈，构成的是电压串联负反馈。
【单选题】There were few people on the street.I saw a man with a knife sneaking up on an old lady.So I first took photos of the man and then called the police. The tool the writer used is ().
A.
a cellphone
B.
a camera
C.
a pepper spray
D.
a handbag
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