As a general rule，all forms of activity lead to boredom when they are performed on a routine(常规) basis.As a matter of fact，we can see this ____1.A____ at work in people of all ____2.D____.For example，on Christmas morning，children are excited about __3.C____ with their new toys.But their ____4.B____ soon wears off and by January those ____5.A____ toys can be found put away in the basement.The world is full of ____6.D____ stamp albums and unfinished models，each standing as a monument to someone's ____7.B____ interest.When parents bring home a pet，their child ____8.C____ bathes it and brushes its fur.Within a short time，however，the
