一看先行词,二分析从句主、谓、宾.
that表人或物,作主语、宾语ThisisthepursethatIlostyesterday.Heisthemanthatisgoodatfishing.
who表人,作主语或宾语Heisthemanwhoisgoodatfishing.
whom表人,作宾语Heisthemanwhommyfatherwastalkingto.
which表物,作主语或宾语ThisisthepursewhichIlostyesterday
whose表人或物,作定语Helivesinahousewhosewindowsfacesouth.