31.   Second, he must be forced to use the box, and third, he must be reinforced for correct elimination.

32.   Second, he must be forced to use the box.

33.   Snookims, the cat, uses his box, faithfully, for years, and then he suddenly starts urinating on the bed.

34.   The airport software also uses rectangular boxes of varying sizes that form and re-form around moving digital images of people.

35.   The light should be able to penetrate the retina, but patients can perform tasks while using the box.

36.   The owner may assume that the animal is refusing to use the box when actually the problem is scent marking.

37.   The owner may assume that the animal is refusing to use the box, when actually the problem is scent-marking.

38.   The Texas laboratory frequently sent shipments to Ames using prelabeled boxes with prepaid postage.

39.   These entities operate for a few weeks, using postal boxes for their return addresses, then shut down and reopen elsewhere under different names.

40.   Too often, postal officials say, criminals use mail boxes with impressive addresses as a front for money-bilking operations.