<span>Once, while I <em>was walking</em> in a park in London, I<em> saw</em> an old strange-looking man. He <em>was sitting</em> on a bench <em>holding</em> a closed book in his hands. I <em>sat</em> down on the bench and looked at the book. I <em>saw</em> that the book <em>was</em> of great interest. It <em>was</em> a very old copy of early Byron's works. I <em>looked</em> at the old man in surprise and <em>undersood</em> that he <em>knew</em> I <em>had sat</em> on the bench because of him and the book he <em>was holding</em>in his hands. I <em>smiled</em>. "It is the last I have," he said and <em>stretched</em> it out to me. I <em>took</em> with the words, "I <em>am</em>a lover of old books."</span>
Case-knife это нож по английскому языку.