总进气管和水管在与操纵台装接前要（）。
A.排净水分
B.吹净泥沙
C.排净空气
参考答案：B
温度3℃比-8℃高______．
The last time we had great fun was _____ we were visiting the Water Park. [ ]
A. how
B. when
C. why
D. where
