We are only small entities in our planet; therefore contributing the world is a demanding endeavor. I do not think that I can greatly contribute toward the greatness of our planet. Since I am not a president or not a very rich person, my potential to contribute is limited. Perhaps, I can make contribution with my daily work or with my other kinds of activities, however this is only tiny contribution. People in charge are responsible and are able to change things in the world. Of course, I can make contributions on local levels, in my community or in my family.
TOEFL listening discussions: How does Dr Beech characterize the assistantship?