About the membrane signal receptors, which statment is not correct（）
A. They can recognize the extracellular signal molecules
B. They can bind to the signal molecules and intitate the cellular responses
C. All membrane receptors are transmembrane glycoproteins
D. There are several different types of membrane receptors in the same cell membrane
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There are some well-known theories about the origin of language, among which______ proposes an extremely specific connection between physical and oral gesture（）
A. the oral-gesture theory
B. the bow-wow theory
C. the pooh-pooh theory
D. the yo-he-ho theory
Chomsky made the distinction between___（）
A. competence and performance
B. comparative linguistics and historical linguistics
C. langue and parole
D. microlinguistics and macrolinguistics
holds that language originated from people’s imitations of animal cries and other sounds heard in nature（）
A. The pooh-pooh theory
B. The bow-wow theory
C. The divine-source theory
D. The yo-he-ho theory
关于电力变压器能否转变直流电的电压，下列说法中正确的是（）
A. 变压器可以转变直流电的电压 B．变压器不能转变直流电的电压 C．变压器可以转变直流电的电压，但转变效果不如交流电好 D．以上答案皆不对
B. 变压器可以转变直流电的电压
C. 变压器不能转变直流电的电压
D. 变压器可以转变直流电的电压，但转变效果不如交流电好
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