1. Their aim is understandable.
    他们的目标是可以理解的。

2. That's an understandable reaction.
    这种反应是可以理解的。

3. Stalin drank very little vodka and seemed to prefer wine, which was understandable for a man from Georgia, a wine-producing land.
    斯大林喝了很少的伏特加酒，他好象更喜欢喝葡萄酒，这对于来自格鲁吉亚的人来说也是可以理解的，因为那里是葡萄酒的产地。