定语从句的引导词若在从句中作主语或宾语，则用which或that。
Do you remember the days(which/that) we spent together?
你还记得我们一起度过的那些日子吗？(关系词在从句中作spent的宾语)
The school(which/that) we visited yesterday is newly built.
我们昨天参观的那所学校是新建的。(关系代词which/that在从句中作宾语)
This is the reason(which/that) our teacher gave us for doing it.
这就是我们的老师给我们的做此事的理由。(关系代词在从句中作宾语)
He gave me a reason that/which was reasonable.
他给了我一个合情合理的理由。(关系代词在从句中作主语)
[即学即练1] 单句语法填空
①He arrived in Beijing on the day when I left.
②The factory where his father works is in the east of the city.
③This is the reason which/that he offered at the meeting.
④Do you know the reason why he is absent?
