This problem had occurred under corner tangential firing and wall opposed firing, and it became even more serious under W-shaped flame double-arch firing.

四角切向燃烧和墙式对冲燃烧方式都有此问题，而W火焰双拱燃烧锅炉则更严重，值得关注。

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The crossbow includes an arch fixed to the center spine, and a trigger mechanism was added to it, which can facilitate targeting and retaining the string, so as to make delay firing.

弩将弓装在弩臂上，并增加了可供瞄准和控弦的弩机，因而可延时发射。

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