句型转换。每空一词，缩略词算一个单词。

1. He visited his uncle yesterday. (否定句)

    He                           his uncle yesterday.

2. The school is 6 kilometers away. (对划线部分提问)

                              is the school?

3. They often go to work by train. (对划线部分提问) 

                              they often go to work?

4. The boy is young. He can't go to school. (把两句合为一句) 

    The boy is              young              go to school.

5. She began to learn the piano at the age of five. (同义句)

    She began to learn the piano              she              five.

对工程造价指数的作用，表述错误的是（）。

A．工程造价指数是施工图预算的依据

B．工程造价指数可以用来估计工程造价变化对宏观经济的影响

C．工程造价指数是进行工程结算的重要依据

D．工程造价指数可以用来分析价格变动趋势及其原因