句型转换。

1. Linlin's home is about 5 kilometers from  school.（对画线部分提问）

    _____ _____ is it from Linlin's home to school?

2. You should take the medicine three times a day.（对画线部分提问）

    _____ should you _____ three times a day?

3. He often goes to the movies once a month.（对画线部分提问）

    _____ _____ he often do once a month?

4. I'm visiting my uncle in France for five days.（对画线部分提问）

    _____ _____ are you visiting your uncle in France?

5. I have to study for my physics test.（改为一般疑问句）

    _____ you _____ to study for your physics test?

患者男，26岁，因上前牙牙面黑色横纹数年要求美齿修复。查体：唇面中央一横纹，与周围分界清晰，探针可探入，探痛(-)

该疾病病因可能为（）

A．细菌作用

B．慢性氟中毒

C．牙胚发育时局部感染

D．磨耗

E．药物沉着