完形填空 通读下面的短文，掌握其大意，然后从每小题所给的A,B,C三个选项中选出一个最佳答案。
I had a very unusual experience（经历）on Sunday. At ten in the morning, I was 1 down the street when a UFO landed right 2 of me. You can imagine（想象） 3 strange it was! An alien 4 and walked down Center Street. I followed it to see 5 it was going, and I was very surprised when it went 6 a souvenir shop. While it was 7 at the souvenirs（纪念品）, the shop assistant called the 8 . Before the police arrived, the alien left the 9 and then visited the Museum of Flight. 10 the alien was in the museum, I called the TV station. Isn’t that amazing!
1. A. arriving B. walking C. looking
2. A. in front B. before C. at
3. A. what B. when C. how
4. A. got in B. got on C. got out
5. A. where B. when C. which
6. A. onto B. on C. into
7. A. walking B. looking C. giving
8. A. police B. teacher C. driver
9. A. school B. shop C. street
10. A. While B. What C. Which