根据以下资料回答第39、40题。
 "Most episodes of absent-mindedness--forgetting where you left something or wondering whyyou just entered a room--are caused by a simple lack of attention," says Schacter. "You're supposedto remember something, but you haven't encoded it deeply." 
Encoding, Schacter explains, is a special way of paying attention to an event that has a majorimpact on recalling it later. Failure to encode properly can create annoying .situations. If you putyour mobile phone in a pocket, for example, and don't pay attention to what you did because you'reinvolved in a conversation, you'll probably forget that the phone is in the jacket now hanging inyour wardrobe(衣柜 ). "Your memory itself isn't failing you," says Schacter. "Rather, you didn'tgive your memory system the information it needed." 
Lack of interest can also lead to absent-mindedness. "A man who can recite sports statisticsfrom 30 years ago," says Zelinski, "may not remember to drop a letter in the mailbox." Women haveslightly better memories than men, possibly because they pay more attention to their environment,and memory relies on just that. 
Visual cues can help prevent absent-mindedness, says Schacter. "But be sure the cue is clearand available," he cautions. If you want to remember to take a medication( 药物) with lunch, put thepill bottle on the kitchen table--don't leave it in the medicine chest and write yourself a note thatyou keep in a pocket. 
Another common episode of absent-mindedness: walking into a room and wondering whyyou're there. Most likely, you were thinking about something else. "Everyone does this from timeto time," says Zelinski. The best thing to do is to return to where you were before entering the room,and you'll likely remember.
Why does the author think that encoding properly is very important?