(1)This is the place ____ I worked last year .
This is the place ____ I visited last year.
(2)Is this the farm____ they visitde the other day?
IS this farm____ they visited the other day?
(3)I never forget the day ____ I spent in the country.
I never forget the day ____ we stayed with him last summer.
请大侠们帮帮吗,告诉答案之余请必须详解为什么!!谢谢谢谢!!