我国防洪的重点是每年的（）和沿海城市有台风暴雨引起的海洪。
A. 暴雨河洪
B. 山洪
C. 泥石流
D. 河堤缺口
Vessel required to have an Automatic Radar Plotting Aid must have a device to indicate the（）.
A. speed of the vessel over the ground or through the water
B. distance to the next port
C. time of the next navigational satellite pass
D. None of the above
将50ml，0.50mol/L的盐酸溶液稀释成0.20mol/L，正确的做法是加水至75ml还是加水至125ml？
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