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C9P21段落大意题

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B段标题

I: seeking the transmission of radio signals from planets

II: appropriate responses to signals from other civilisations

III: vast distances to Earths closest neighbours

IV:assumptions underlying the search for extra-terrestrialintelligence

V: reasons for the search for extra-terrestrial intelligence

VI: knowledge of extra-terrestrial life forms

VII: likelihood of life on other planets

C段标题

I: seeking the transmission of radio signals from planets

II: appropriate responses to signals from other civilisations

III: vast distances to Earths closest neighbours

IV:assumptions underlying the search for extra-terrestrialintelligence

V: reasons for the search for extra-terrestrial intelligence

VI: knowledge of extra-terrestrial life forms

VII: likelihood of life on other planets

D段标题

I: seeking the transmission of radio signals from planets

II: appropriate responses to signals from other civilisations

III: vast distances to Earths closest neighbours

IV:assumptions underlying the search for extra-terrestrialintelligence

V: reasons for the search for extra-terrestrial intelligence

VI: knowledge of extra-terrestrial life forms

VII: likelihood of life on other planets

E段标题

I: seeking the transmission of radio signals from planets

II: appropriate responses to signals from other civilisations

III: vast distances to Earths closest neighbours

IV:assumptions underlying the search for extra-terrestrialintelligence

V: reasons for the search for extra-terrestrial intelligence

VI: knowledge of extra-terrestrial life forms

VII: likelihood of life on other planets