高分求几道高一英语题~高手帮忙解答~急

高分求几道高一英语题~高手帮忙解答~急
1.They climbed the mountain（）many people were planting trees,and()lotsheep were eating grass.
A.where,where B.that,that C.where,that D.that,which
2.It was in that house()he used to live()thesecret meeting was held.
A.where,where B.that,that C.what,where D.where that
3.Is it the country ()you studied()you are going to visit next week?
A.in which which B.where that C.that that D.which that
4.This is the tallest building here,()you can enjoy fine view of the city.
A.from its top B.from which top C.from the top of which D.from whose top of which
5.They stayed with me three weeks,()they drank all the wine I had.
A.which B.during which time C.which time D.during which
不仅要答案,还要详细讲解原因~谢谢了!