17.Last Saturday afternoon,I took a walk with some of my friends in the central park.The park was full (93)of freshness and greenness of spring,with the sun shining and birds(94)ssinging.When we were enjoying the fantastic scenery around us,something unpleasant (95)ccaught my eye.A young couple in a boat were eating things,talking and laughing loudly as (96)though/if they were the only people in the world.What's (97)wworse,they threw paper bags and banana skins into the lake,totally (98)ignoring (忽視)the sign"No Littering"nearby.What a shame!
Such behavior left me (99)ddeep in thought.If all visitors to the park do as the couple did,the lake will be severely (100)polluted (污染)and soon turned into a huge dustbin.I think all of us should mind our behavior in (101)public (公共)places and do what we can to protect the environment.(102)Onlyin this way can we live in more comfortable and beautiful surroundings.