What is the duty of an occupier to an invitee?

The duty owed to an invitee is summarized at page 645-647 of the above-mentioned text, Canadian Tort Law, at page 645 the following appears: “The duty that an occupier owes to an invitee was expressed by Willes J. in Indermaur v. Dames as follows: …we consider it settled law, that he, using reasonable care on his part for his own safety, is entitled to expect that the occupier shall on his art use reasonable care to prevent damage from unusual danger, which he knows or ought to know;… In Smith v. Provincial Motors Ltd. It was suggested that, once it is decided that the entrant is an invitee, four additional questions should be asked: First, was there an unusual danger? Second, did the defendant know or have reason to know about it? Third, did the defendant act reasonably? Fourth, did the plaintiff use reasonable care for safety or did the plaintiff voluntarily incur the risk?”