补全短文
A. sponsoring book discussion clubs B. how they can best adapt C. short attention spans D. accomplishments are admired Phrases: A. and knowing that their【T13】______ B.【T14】______to such changes C. such as displaying their artwork or【T15】______ D. As teenagers have【T16】______ Teachers need to be aware of the emotional, intellectual and physical changes that young adults go through. And they also need to give serious thought to【T17】______Growing bodies need movement and nutrition, but not just in ways that emphasize competition. Because they are adjusting to their new bodies and a whole host of new changes, teenagers feel especially awkward in the presence of others and need the confidence that comes from achieving success【T18】______However, the typical teenage lifestyle is already filled with so much competition that it would be fair to organize activities in which winners outnumber losers,【T19】______A variety of small clubs can provide multiple opportunities for leadership, as well as practice in successful group dynamics. 【T20】______, activities should be organized in such a way as participants can remain active as long as they want, then proceed to something else without letting the rest down.