句型转换。

1. They have never been to an English-speaking country. (变为一般疑问句)

                 they             been to an English-speaking country?

2. She has been a flight attendant for two years. (对画线部分提问)

                               has she been a flight attendant?

3. His father has been to America twice. (对画线部分提问)

                has his father been to America?

4. Linda is taller than any other girl in her class.(改为同义句)

    Linda is                         girl in her class.

5. I prefer tea to coffee.(改为同义句)

    I prefer to have tea              have coffee.

锅炉墙式再热器的管子规格为（）材质（）。