阅读理解。

Dear Grandma,

     I've been in Bluelake for two months now. It's a beautiful small city. Schools here begin at the end

of August. I like my school and I'm having a great time teaching Art History here.

     I'm now living in an apartment with a friend. From the window of my bedroom, I can see a beautiful

green hill with flowers and trees. Many people go there to have a picnic or to fly kites. I enjoy taking a

walk there every day after work and watching the people. 

    I miss you very much, Grandma, and I hope you can come and visit me here some day.

                                                                                                                              Love,

                                                                                                                              Jude

1. What is Bluelake?

A. A city.

B. A park.

C. A school.

D. An art museum.

2. What is Jude doing in Bluelake?

A. Working.

B. Studying.

C. Visiting a friend.

D. Taking a vacation.

3. Which picture best shows what Jude sees out of his bedroom window?

         A                     B                         C                          D

在DX200系统中，N+1/R和N+1/L的备份方式有什么区别？