【单选题】听力原文:(A)They're setting the table for a meal. (B) They're concentrating on some documents. (C) They're taking off their glasses. (D)They're taking their seats for a meeting.
【简答题】过共晶白口铸铁碳的质量分数为 ,其室温组织为 。
【简答题】听力原文:(A) They're shaking hands. (B) They're moving some chairs. (C) They're playing a . (D) They're posting something on the board.
【单选题】听力原文:(A) They're standing in a line. (B) They're studying a map. (C) They're buying some magazines. (D) They're looking at the same book.
【简答题】亚共晶白口铸铁碳的质量分数为 ,其室温组织为 。
【单选题】听力原文:(A) They're signing some forms. (B) They're standing next to the sign. (C) They're putting up signs. (D) A man is pointing into the distance.