经过变换氮气加热器加热后的氮气进入（）前。
A、增湿塔
B、变换炉一床
C、变换炉二床
D、减湿塔
参考答案：B
- __________ that he managed to get the information? -Oh,a friend of his helped him. [ ]
A. Where was it
B. What was it
C. How was it
D. Why was it
下列属于动物生长早熟部位的是（）。
A、体长
B、体深
C、头、腿
D、羊
