40．A．easy                    B．happy                  C．dangerous              D．difficult

    A

    Grygori Pilikian spent his 114th birthday the other day and some reporters visited him to find out the secret of a long life．

    “The secret of a long life is happiness，” Grygori said．“If you are happy，you will live a long time．”

39．A．explore（考察）  B．invent                  C．find                      D．make

38．A．problem              B．question                C．thing                     D．lesson

37．A．later                    B．earlier                 C．longer                    D．less