根据句意，用括号内所给动词的适当形式填空。

1. They ______ (come) to China two months ago.

2. Where ______ (be) she last week?

3. The twins ______(be) at school this morning.

4. ______ he ______ (tell) you a story last Sunday?

5. We ______ (not watch) TV last night.

6. Let me ______ (help) you.

7. Listen! Sue ______ (sing) an English song.

8. I ______ (help) my mother do housework tomorrow.

9. Tom always ______ (get) up at six o'clock in the morning.

10. ______ (not close) the door.

自然疫源性疾病是指（）

A.病原体能通过动物传播到人的疾病

B.以动物作为传染源，并在动物间传播的疾病

C.一种疾病的病原体，不依靠人而能在自然界野生动物中生存繁殖

D.一种疾病的病原体不依靠人而能在自然界野生动物中生存繁殖，并只在一定条件下传给人和家畜

E.经常在某一地区某一人群呈地方性流行的疾病