But where could such a hound lie concealed (но где могла прятаться: «находиться, прячась» такая собака), where did it get its food (где она добывала пищу), where did it come from (откуда она взялась; to come from — происходить /из какой-либо местности/), how was it that no one saw it by day (как так /могло/ быть, что никто ее не видел днем = при свете дня)? It must be confessed that the natural explanation (нужно признать, что объяснение /всего этого/ естественными /причинами/) offers almost as many difficulties as the other (влечет за собой: «предлагает» не меньшие затруднения: «почти столько же затруднений, как и другое»). And always, apart from the hound, there was the fact of the human agency in London (и неизменно присутствовал, помимо собаки, фактор человеческой деятельности в Лондоне), the man in the cab (человек в кебе), and the letter which warned Sir Henry against the moor (и письмо, предупреждавшее сэра Генри /об опасности, грозящей ему/ на болотах). This at least was real (это, по крайней мере, было реальным), but it might have been the work of a protecting friend (но это могло бы быть делом рук друга; to protect — защищать) as easily as an enemy (столь же легко, как и врага). Where was that friend or enemy now (где находился этот друг или враг сейчас)? Had he remained in London (остался ли он в Лондоне), or had he followed us down here (или последовал за нами сюда)? Could he — could he be the stranger (неужели это тот незнакомец) whom I had seen upon the tor (которого я видел на скале)?
offer ['Of@], almost ['O:lm@ust], enemy ['enImI]
But where could such a hound lie concealed, where did it get its food, where did it come from, how was it that no one saw it by day? It must be confessed that the natural explanation offers almost as many difficulties as the other. And always, apart from the hound, there was the fact of the human agency in London, the man in the cab, and the letter which warned Sir Henry against the moor. This at least was real, but it might have been the work of a protecting friend as easily as an enemy. Where was that friend or enemy now? Had he remained in London, or had he followed us down here? Could he — could he be the stranger whom I had seen upon the tor?