肃立: stand as a mark of respect 短语和例子肃立致哀 stand silently mourning; 奏国歌时全场肃立。 all those present were standing solemnly when the national anthem was played
致哀: express one's condolences (to); pay one's respects to 短语和例子他们向革命烈士致哀。 they paid their respects to the revolutionary martyrs