有些还打到罐子，那是他不须怀疑的，因为它们发出声音来了。他见他们没有回音，所以丢第二次和第三次的石子，他猜想不出他们对暗号何以没有反应。
As there was no response , he threw stones a second and a third time , and could not imagine why there was no answer to his signal .
对暗号