皮皮学，免费搜题
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搜题
【单选题】
The text indicates that ______.A.
we are lack of food innovations
B.
many economists are wrong in investigating the economics of technological innovations
C.
profit-oriented business people believe that innovation can increase their incomes
D.
we cannot disregard the effects of culture in guiding technical change
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【单选题】音频信号按质量可分成电话质量的语音、调幅广播质量的音频信号和高保真立体声信号。其中高保真立体声信号频率范围是（）。
A.
300Hz～3.4kHz
B.
50Hz～7kHz
C.
50Hz～20kHz
D.
10kHz～20kHz
【简答题】According to the movie clip, 1.__________ (movie name) is No. 1 on the list, and it was first released in 2.________(which year?).