例句：
1、How sad that all his hard work should come to nothing.
他的'所有辛勤劳动竟全部付诸东流，太让人伤心了。
2、It's a sad fact that many of those killed were children.
让人难以接受的是遇难者中很多是孩子。
3、It was sad to see them go.
看着他们离去，真让人难过。
