作为承运人必须向旅客开具接受行李的单证，同时向旅客收取规定的运费。
参考答案：对
—What about the student in your class, Mr. Wang?
—The doctor said that sleep caused him poor memory and poor concentration.
A．lacking of
B．lacked in
C．lacking
D．lack for
疠气与六淫邪气最主要的区别是（）
A.发病与季节有关
B.发病与地区有关
C.病情重笃
D.发病急骤
E.传染性强
