Unit 118：Mix'em up第118单元：混合做多种运动People enjoy exercising more when they engage in more than one activity,says Dr.Brownell.布洛耐尔博上说:“人们做的运动不只一项时会比较喜欢运动。”A variety of exercises gives your body a better all-around workout and stretches your easily bored mind.各式各样的运动使你更能全身活动，也可以让你不那么容易感到无聊。Sometimes a simple stretch is all you need.At other times,you want to go for the burn in an aerobics dance class.有时候你需要的只是伸伸懒腰，有时候你会想到有氧舞蹈教室去燃烧脂肪。Another day you may decide to lift weights or go for a long bike ride.改天说不定你会决定去举重或骑脚踏车呢。