Read the following paragraph (the second paragraph of Passage B) and find the main idea by applying the reading skill “Skimming”. I trust that as you prepared for this day, you must have taken some time to contemplate what you are searching for in your undergraduate education. Today we are living in a time of great change. New medical discoveries in science are revolutionizing the way we treat human disease as well as challenging us with deep and complex ethical questions. The changes we have brought in our environment — from global warming to the reduction and extinction of various flora and fauna — force us to face the question of how we will build a model for sustainable existence. Events around the world remind us that we share a small planet among peoples with different beliefs, hopes and cultures, and that understanding and appreciating their ambitions and their history will be critical to building a better world for all. The main idea of this paragraph is: The time we are living in is (1)_____________ and we have to think about (2)_______________. (答案从文章中找)