已知函数f（x）=ln（x+a）﹣x²﹣x在x=0处取得极值

（1）求实数a的值；

（2）若关于x的方程f（x）=﹣$\frac{5}{2}$x+b在区间0，2上有两个不同的实根，求实数b的取值范围．

补全对话。

A. She is a doctor. 

B. How does she go to work?

C. What does your father do?

D. I want to be a pilot. 

E. Do you want to be a pilot, too? 

Bill: Hi! Mike! ____       

Mike: He is a scientist.  

Bill: Does he like his job?           

Mike: Yes, but he's very busy.

Bill: What about your mother?      

Mike: ____ 

Bill: Oh, doctors always work hard.  

Mike: Yes, but it is interesting. 

Bill: ____                

Mike: She goes to work by bus. 

Bill: What are you going to do when you grow up (长大)? 

Mike: ____

Bill: It's cool.      

Mike: ____   

Bill: No, I want to be a writer.