根据句意和词首字母（或汉语）提示完成单词。

l.  The plane t         off from Tokyo at 20:00 last night.

2. Mr Green c         his hair in the barber shop this morning.

3. Mrs Black         (买)her daughter a nice skirt yesterday.

4. Mr Jackson is a         (奇怪的)man. He always wears a hat all the year round.

5. To my         (吃惊)，the alien was shopping.

6. After I reached home last night, my father s       (说)to me," Have you finished your homework?"

7. The boy was walking down the street when the UFO l         .

8. An a         was visiting the museum when a girl called the TV station.

简述甲壳溃疡病发生的原因。