高一英语（定语从句）高手进~
用正确的介词+关系代词填空
1,As is known to us all,the age_____ _____children can go to school is 7.
2,Mrs Zhang often tells us that spring is the time_____ _____people often go sightseeing.
3,He borrowed a book the other day,the author_____ _____is a worker.
4,Thank you for you help,_____ _____we could not have finished the work on time.
5,Do you remember the building_____ _____flew a fed flag all the year round?
6,The reason_____ _____I bought the roses is that Mary likes them.
7,He built a telescope_____ _____he could study the skies in hie free time.
哪位会这些题啊?请把答案和用法简单写一下.好的可以追加分数.谢谢.