翻译33-37划横线的句子: (33)Ifirsttookupwalkingasameansofescape.(34)Afterabusymorninginmyoffice,Ifounditrefreshingtotakeastrollatlunchtime,tobreathethefreshairandfeelthesun.Anotherwalkinthecoldnightairwas,Idiscovered,anexhilaratingwaytounwind.(35)Walking--likeswimming,bicyclingandrunning--isanaerobicexercisewhichbuildsthecapacityforenergyoutputandphysicalendurancebyincreasingthesupplyofoxygentoskinandmuscles.(36)Suchexercisemaybeaprimaryfactorinthepreventionofheartandcirculatorydisease.(37)Asprobablytheleaststrenuous,safestaerobicactivity,walkingisthemostacceptableexerciseforthegreatestnumberofpeople.Walkingatcomfortablespeedimprovestheefficiencyofthecardio-respiratorysystembystimulatingthelungsandheart,butatamoregradualratethanmostotherformsofexercise. ____33_____
我最初开始散步是作为一种脱身之计。