Bears and humans often meet in National Parks．Although campers and hikers are warned not to feed the bears，many people ignore these warnings and feed the beasts anyway．When bears are used to people's food，problems soon arise．

Bears like to eat a large variety of things，both meat and vegetable．Without human assistance，bears live nicely on roots，twigs，leaves of trees，insects and small animals．With people around，the bears'tastes quickly expand to include sandwiches，hot dogs，hamburgers，and anything else they can temp humans into giving up．

Bears often develop clever strategies for getting people to let go their food supplies．More often than not，an unsuspecting hiker has taken off his or her pack for a rest only to have a bear charge out of the woods，grab the pack and quickly disappear into the underbrush with it．Hanging the pack on a tree branch won't help．Bears have been known to climb up，jump off，and catch the pack on the way down．One mother bear stretched up with her baby on her shoulders to reach a pack stored on a pole．Many bears threaten people into giving up their supplies．Although a bear is unlikely to attack a person and would probably run away if screamed at，few people are willing to do so．Most people drop the pack and run the other way．This，of course，delights the bear．In some places，the Park Service installed some metal barrels with lids to help campers keep their supplies safe from bears．Although the bears were unable to open these containers，the effort was less than successful．Most campers，unable to tell the metal drums from rubbish cans，never used them for the intended purpose．

67．Feeding bears on people's food___．

A．brings the people a lot of fun B．can cause problems

C．often causes injuries and deaths D．helps bears survive

68．If people had never fed bears，the bears___．

A．might be satisfied with what they had originally

B．would have starved long before

C．wouldn't have