1 . Even if you’re a couch potato like me, you’ll know the benefits of running. But if you’re a real fitness fan, the ____ running challenge is to participate in a marathon. While many runners’ ______ is to beat their personal best and cross the finishing line without ______ , they’re also doing it for a good cause – to generate funds for ______ .

But just like other ______ events, the marathon also ______ a massive carbon footprint. Thousands travel - some by plane - to the location, and ______ from food packaging and goody bags gets left behind by ____ and runners. For example, during the London Marathon in 2018, ______ 47,000 plastic bottles were collected. This is becoming a big issue for cities – how to ______ a worthwhile event, encouraging people to exercise and help charities, while ______ the environment?

Several cities have ______formal plans to reduce their environmental influence and ______ sustainable (可持续的) ideas. One event in Wales, for example, introduced the recycling of ______ running equipment. The London Marathon tried to deal with the environmental problem by ______ the number of drink stations on the running route, ______ water in paper cups and offering some drinks in edible (可食的) seaweed capsules. They also tried new bottle ______ made from recycled plastic so 700 runners could ______ water bottles with them during their run.

Dr Andrea Collins from Cardiff University told the BBC: "Training for a marathon makes you more sustainable in day-to-day activities. I started walking or running to work every day and _______ private cars altogether. Being environmentally friendly becomes a good ______ ." So while you not be an excellent runner in a marathon, let’s hope the event, in terms of sustainability, certainly is!