【判断题】移动闭塞的线路依旧有物理层次的闭塞分区划分。( )
【单选题】According to the passage, it is difficult to interpret the results of certain treatments for SARS because______.
A.
patients were in different countries .
B.
patients were given medicines in widely different settings
C.
patients were at different stages of the illness
D.
these conditions had no standardized measurements or controlled situations
【单选题】在IS-LM模型中,如果经济在衰退区间运行,那么最有效的政策是
【简答题】氮质血症(azotemia)(名词解释)