【单选题】When two oil separators are working in series, they should work with ____.
B.
first one as clarifiers, second one as purifier
D.
first one as purifier, second one as clarifier
【单选题】圆环体的回转轴为铅垂线,在其正面投影中,中心线和轴线共有几条
【简答题】A.It is a book written only for classroom reading. B.It is a book on education. C.It has a vocabulary of only two hundred words. D.It was written by a child.
【单选题】中国文学史上第一部由文人独立创作的长篇小说,也是世情小说的开山之作的是()。
【单选题】中国第一部由文人独立创作的长篇世情小说是?
【简答题】Whenever Olive is misunderstood by her friends, she would like to write to them for clarification,______(而不是面对面交流).