1、
Oh, yes, we sailors are like freemasons, and recognize each other by signs.
哦, 是的, 我们水手就象是互济会会员,可凭某种暗号互相认识的.
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2、
They used elaborate secret codes, as when the names of trees stood for letters.
他们使用了复杂的暗号，比如用树的名称代表字母。
《柯林斯高阶英汉双解学习词典》
3、
The back shows petroleum prospecting and the countersign is the same as the 5 yuan.
此券背面图是石油勘探,暗号和五元券一样.
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4、
Then the bandit thrice imitated the cry of a crow; a croak answered this signal.
于是那强盗学了三声鸡叫, 一声老鸦叫答复了这个暗号.
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