Now, it was past three o'clock, according to Mrs. Smith, when they got the boat. It would be quite bright, and people would be about in an hour or so. Therefore, I argued, they did not go very far. They paid Smith well to hold his tongue, reserved his launch for the final escape, and hurried to their lodgings with the treasure-box. In a couple of nights, when they had time to see what view the papers took, and whether there was any suspicion, they would make their way under cover of darkness to some ship at Gravesend or in the Downs, where no doubt they had already arranged for passages to America or the Colonies."
根据斯密司太太所说，他们在斯密司码头上船的时候是三点钟，再过一个多钟头天就要大亮，行人也多了，所以我认为他们是不会走得太远的。他们给足了斯密司钱，叫他不要声张，并预订了他的船，以备最后的远行，然后携带宝物回到巢穴。在一两天内，他们会看看报纸，听听风声，再选择一个夜晚从葛雷夫赞德或肯特大码头乘上他们已经订好船位的大船，逃往美洲或其他殖民地去。
hold one's tongue:在这里应理解为“保持沉默”。
例如：
There were a lot of things I wanted to say, but I thought I’d better just hold my tongue.
（有很多事情我想说，但我想我最好还是闭嘴。）
The issue is very sensitive. You need to hold your tongue.
（这个问题很敏感，你要保持沉默。）
我们再来看两个含有hold的短语
hold water：站得住脚，经得起检验
This argument simply cannot hold water in Europe.
（这个论点在欧洲根本就站不住脚。）
hold your horses沉住气
Michael: Hold your horses. Don't leave without finishing your report first.
迈克尔：慢着，别忘了先把你的报告写完再走。