On both previous occasions, he had knocked timidly and with some dread of attracting notice; but now when he had just discarded the thought of a burglarious entry, knocking at a door seemed a mighty simple and innocent proceeding.

前两次，他都是胆怯地敲门，生怕引起注意。但是现在，当他刚刚打消了盗窃进入的念头时，敲门似乎是一种非常简单和无辜的行为。

They must have got, I reasoned, upon the roof of the outhouse where Northmour used to keep his photographic battery; and from thence, either by the window of the study or that of my old bedroom, completed their burglarious entry.

我推测，他们一定是到了外屋的屋顶上，诺斯穆尔过去常常用来存放他的照相电池；然后，从书房的窗户或我以前卧室的窗户，完成了他们的入室盗窃。