一但

• Tenacious . once they bite , they never let go
  一但咬住就绝不松口
• I would be happy to visit you at your earliest convenience
  一但你感到方便我会非常高兴去探望你
• But once that strip turned blue . .
  一但验孕器变蓝色以后. .
• Lucia : once entering the demon world , you may never be able to return
  一但进入魔界，你就不可能回来了。
• If one of them gets distracted ,
  一但他们有人心思不集中
• But once that strip turned blue
  一但验孕器变蓝色以后
• One but discovery should inform concerned branch puts to death instantly
  一但发现应立即通知有关部门处死。
• Then i had another one . you know what i ' m like when i get started
  然后我又吃了一块，你知道我一但开始就收不住
• Once a needle breaks , it is necessary to remove it as soon as possible
  一但发生断针时，及时取出断裂针头是必要的。
• Once he began warming in the bullpen , manager would be forced to use him
  一但需要他在牛棚开始热身，就必须用到他。