定从句型
1、主句+who/whom/that/which/whose+从句
This is an old computer which/that works much slower.
I happened to meet the professor (who/whom) I got to konw at a party.
2、主句+when/where/why+从句
Potatoes can be grown in places where(=in which) it is too cold to grow rice.
I shall never forget the days when(=during which) we worked on the farm.
I have come around to explain the reason why(=for which) I was absent from the meeting.
