试射用的模型类似于大炮。
很显然要很多人才能拉动大炮，这不仅使大批的人无法工作而且意味着根据需要改换姿势是一种可能治他们于死地的严酷的考验。
It clearly took more than one man to move the cannons, which not only put a large number of men out of action, but meant changing positions as needed was an ordeal that might get them killed.
集中大炮火力于某一点，那便是他胜利的秘诀。
The key to his victory was to make the artillery converge on one point.
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