Premise: Granted, the Web is not yet a picture of efficiency itself.

Hypothesis: The World Wide Web is not yet as efficient as it could be.
Answer: yes

Premise: Well, then, listen." He sat down on the corner of the desk and took out a cigarette.

Hypothesis: He hadn't had a cigarette all day.
Answer: it is not possible to tell

Premise: By itself, the dollar amount of national saving is not a particularly meaningful indicator of the portion of the nation's income that is not consumed.

Hypothesis: National saving's dollar amounts are a meaningful indicator of how much the nation hasn't consumed.
Answer: no

Premise: Note the masterful Ren?ais?sance carving of the oak doors on the central and north portals.

Hypothesis: The doors at the central and north portals are decorated with Renaissance carvings.
Answer: yes