McDonald's, Greggs, KFC and Subway are today named as the most littered brands in England as Keep Britain Tidy called on fast-food companies to do more to tackle customers who drop their wrappers and drinks cartons (盒子) in the streets. Phil Barton, chief executive of Keep Britain Tidy, ____ its new Dirty Pig campaign, said it was the first time it had investigated which ____ made up "littered England" and the same names appeared again and again. "We ____ litterers for dropping this fast food litter ____ the first place but also believe the results have pertinent (相关的) messages for the fast food ____. McDonald's, Greggs, KFC and Subway need to do more to ____ littering by their customers." He recognised efforts made by McDonald's, ____ placing litter bins and increasing litter patrols, but its litter remained "all too prevalent". All fast food chains should reduce ____ packaging, he added. Companies could also reduce prices ____ those who stayed to eat food on their premises, offer money-off vouchers (代金券) or other ____ for those who returned packaging and put more bins at ____ points in local streets, not just outside their premises. A ____ for McDonald's said:  "We do our best. Obviously we ask all our customers to dispose of litter responsibly." Trials of more extensive, all-day litter patrols were ____ in Manchester and Birmingham. KFC said it took its ____ for litter management "very seriously", and would introduce a programme to reduce packaging ____ many products. Subway said that it worked hard to ____ the impact of litter on communities, ____ it was "still down to the ____ customer to dispose of their litter responsibly". Greggs said it recognised the " continuing challenge for us all ", ____ having already taken measures to help ____ the issue.