It is indicated in Paragraph 1 and 2 that______.
A. all airlines provide Wi-Fi Internet service
B. aircraft-communications" frequency is higher than that of Wi-Fi
C. airlines provide Wi-Fi service selectively
D. not all mobile phones" signal will interfere with navigation
The main idea of the text is that______.
A. accents are unfortunately often used to reinforce preexisting linguistic stereotypes
B. accents are used to identify the social background of a speaker
C. accents are generally used to form. negative opinions of the speaker
D. we must stop discriminating against people due to accent
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