I．单项选择 从每小题所给的四个选项中选出能够完成或回答这一小题的最佳答案。(共15小题，每小题1分，共15分)

1．David is ______ eight-year-old boy with short black hair.

     A. /                            B. a                     C. an                   D. the

2．Nancy took her temperature and found she had a ______.

     A. cough                      B. toothache               C. cold                      D. fever

3．― ______ do you usually share happiness with?

― My parents and my best friend.

     A. Who                       B. Whose                   C. What                     D. How

4．I like hiking in the forest because the air is pretty ______.

     A. free                         B. dirty                      C. polluted                 D. fresh

5．Ladies and gentlemen, attention please! I have ______ important to tell you.

     A. nothing                   B. something              C. everything              D. anything