选择题：A. under B.over C. as D. when E.ofHappiness is a c

A. under B.over C. as D. when E.of
Happiness is a choice;you can choose to be sad when everything is going well for you and
you can choose to be happy even _____1 nothing seems right.To be happy at all times,you need
to make happiness a habit and not just an act.Scientists believe that 20 minutes of exercise can
make you happy regardless of how sad you may be.Exercise raises your heart rate and triggers a
surge _____2 hormonal changes._____3 your heart begins to pound,certain hormones are
released which create a sense of total well being and you begin to feel well again,the mind stress
is gone and everything is_____4 control.Another thing you can do is take a walk,this works for me
all the time.When you take a walk,you are able to think____5 matters that are bothering you and
come up with solutions to them.