同义句转换，每空一词。

1. To eat a balanced diet is very important.

    ________ very important ________ eat a balanced diet.

2. They are watching TV at home now.

    They are watching TV at home ________.

3. What's wrong with your sister?

    What's ________ with your sister?

4. She has a sore throat.

    There is something ________ her throat.

5. There is a lot of milk in the bottle.

    There is ________ milk in the bottle.

某建材批发企业（小规模纳税人），当月销售建材15000元（不含税）向税务机关申请代开增值税专用发票，另销售建材5000元（不含税）未开具发票，下列说法正确的是（）。

A.该企业需缴纳增值税600元

B.该企业申请代开增值税专用发票时不需预缴税款

C.该企业申请代开增值税专用发票时需预缴税款

D.该企业代开增值税专用发票已经缴纳的税款，在当月将发票全部联次追回后可以向主管税务机关申请退还