按要求改写下列句子，每空一词。

1. We have a good time in school. (同义句转换)  

    We                   in school.  

2. My aunt buys hamburgers for five dollars. (同义句转换) 

    My aunt          five dollars          hamburgers.

3. Across from the park is an old hotel. (同义句转换)

                       an old hotel across from the park.

4. My pen pal speaks English. (变为一般疑问句)

             your pen pal          English?

5. The pay phone is between the shop and the bus stop. (就划线部分提问)

                       the pay phone?

1L0.1mol·L^－1的K₂SO₄溶液中

A．K^＋的物质的量为0.1 mol

B．SO₄^2－的物质的量为0.2mol

C．K^＋的物质的量浓度为0. 1mol·L^－1

D．SO₄^2－的物质的量浓度为0. 1mol·L^－1