A．Your brain will regard it as the right thing．3
B．You will be in a bad mood for a long time 
C．There will be no resources for the positive．
D．It will be difficult to be grateful again．

A．Happy people tend to be more capable．
B．Happy working environment raises sales．
C．Happiness leads to business efficiency．
D．Happiness makes businessman healthier．

A．To help people survive．
B．To give people confidence．
C．To give people the information about the outside world．
D．To make up most of the information about the outside world．