Courtesy costs nothing. Lower the toilet seat after use. Let the people in the elevator exit before you enter. Return shopping carts to their designated areas. When you borrow something， return it better shape (filled up， cleaned) than when you got it.
The Langlands program is a bridge between the discrete and the continuous.
我对人们被迫过双重生活的方式感兴趣。
造纸行业有责任在环境管理方面引领潮流。