sad的副词是

　　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。

　　The increase in crime is a sad reflection on our society today.

　　犯罪的'增加令人遗憾地反映了当今社会不太好的一面。

　　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。