资料题：Which of the following is NOT mentioned is the internally generated time wasters（  ）。

As is depicted in the picture entitled "cries from our descendants" ,a boy is calling on his ancestors - citizens today throughout the world- to ensure a better environment and a greater abundance of natural resources for future generations.With a forced smile on the face, he is crying bitterly and desperately.Such a scene can just put us deep in thought.The drawer of the picture intends to force us to ask ourselves some very thought provoking(发人深省的) questions concerning nature conservation.Are we willing to be more conservativein our life requirements, and are we willing to moderate our use of the world's resources for ourdescendants? Can we, in fact, reduce our consumption of petroleum, coal and electricity, in order to reduce the pollution and environmental pressures created by excessive energy use and to a allow others to live a better life? Are we willing to spend more money for pollution control and environmental restoration? Are we willing to devote more effort to recycling? Can we moderate our demand for fat rich diets and super-processed convenience food? These are some of the central issues of the present day world, and ones on which the quality of present and future environments may depend.As citizens in the modem world, it is our duty to give thought to the living environment andconditions of or offspring.We must take positive actions to remedy the worsening situation,which is sadly threatening to ruin every corner of the world.Only in this way can the boy stop crying and show some respect to his ancestors.