物理层的主要功能是透明地完成相邻节点之间原始（ ）的传输。

(单选题)What does the Brazilian scientist Crodowaldo Pavan say about (单选题)Which of the following statements is true about the organiza (单选题)Which of the following statements is NOT true about NGOs in (单选题)According to the passage, Brazil is the world's ( ) soybe (单选题)According to the passage, the issue in dispute in Brazil is (单选题)The aim of the passage is to_________. ( ) (单选题)If you want to keep quieter from the loud engines, which sea (单选题)What can we learn from the passage? ( ) (单选题)Which is NOT the reason that it's better to buy a seat on th (单选题)Choose a best title for the last but one paragraph. ( )