普通话声母“b”与“p”的发音区别在于（ ）。

(单选题)The best title for this passage may be ______. (单选题)As for the details of the system designed by researchers, wh (单选题)As for the characteristics of the energy management system, (单选题)Which of the following statements is INCORRECT about hybrids (单选题)The underlined word “chauffeuring” in the passage is closest (单选题)All following factors contributed to the drop of the resourc (单选题)Which of the following statements about source-rich economie (单选题)What political problem exists in mining industry? (单选题)According to the passage, mining is different from other ind (单选题)The underlined word “volatility” in the first paragraph mean