2 ¤·¤é¤Ê¤¤¤Ò¤È¤«¤é ¤Ê¤ó¤É£¨ £©¤Ç¤ó¤ï¤¬ ¤«¤«¤Ã¤Æ ¤¤â¤Á¤¬ ¤ï¤ë¤¤¤Ç¤¹¡£
a ¤â b ¤Ë c ¤Î d ¤¬
3 ¤Æ¤ó¤é¤ó¤«¤¤¤Ç¡¸¤º¤Ð¤é¤·¤¤¤Ç¤¹¤Í¡£¡¹£¨ £©¤¤¤ï¤ì¡¢¤¦¤ì¤·¤«¤Ã¤¿¤Ç¤¹¡£
a ¤ò b ¤Ë c ¤È d ¤Ç
4 ¤ª¤«¤·¤¤¤Ç¤¹¤Í¡£¤±¤·¤¿¤Ï¤º¤Î ¥Æ¥ì¥Ó£¨ £©¤Ä¤¤¤Æ ¤¤¤Þ¤¹¡£
a ¤ò b ¤¬ c ¤Ë d
ÒÔÉÏÊÇÈÕÓïN4Èý¼¶Ó﷨ģÄâÌâ(6)µÄËæ»úժ¼£¬Òª²é¿´È«ÎÄÇëÏÂÔØÍêÕû°æ¡£