This sentences is biased because it contains the opinion of his writer. By saying that the Titanic was "the most impressive" ship ever built, the writer is not giving an objective opinion, but one filled with his own thoughts and points of view.
In "the fun they had . " tommy finds a book. The book's pages are yellow and crinkly becauseitwasanoldbookwhichexcitednearlya100yearsagowhenthebookswereprintedin spiteofbeingsavedandshowninthetelevisionscreenthattommyandMargiehad.
I would start with simple definitions to teach them, the words would depend on the grade they are in, then the words would get harder as we make progress.
Explanation: Hope this helps:).......if not sorry for wasting your time:)