完形填空。 A young man works hard 1 his lessons. He is very busy 2 . He doesn't have time 3 . After 4 , he falls ill. Every night, when he goes to bed, he 5 his eyes and tries to sleep. But he can't. He thinks, 'I must go to 6 the doctor.' He tells the doctor, 'I can't go to sleep at night.' 'Try counting(数) 7 . When you 8 1,000, you'll be asleep,' says the doctor. The next day the man goes 9 the doctor's office. 'Well,' says the doctor, ' 10 are you today?' 'Well,' the man says, 'I tried counting one, two, three …up to 1,000. 11 when I reached 569, I began to feel sleepy (犯困的). I had to 12 and 13 some tea. Then I went 14 counting up to 1,000 again. But I 15 couldn't fall asleep.' (     )1. A. in (     )2. A. study (     )3. A. rest (     )4. A. sometimes (     )5. A. closes (     )6. A. A look (     )7. A. colors (     )8. A. get (     )9. A. to back (     )10. A. where (     )11. A. So (     )12. A. get off (     )13. A. eat (     )14. A. to (     )15. A. still B. on B. studying B. to rest B. sometime B. opens B. call B. numbers B. go B. back B. when B. But B. get to B. drink B. in B. already C. at C. to study C. resting C. some time C. washes C. see C. ages C. arrive C. back to C. which C. Then C. get up C. take C. on C. again D. for D. studies D. of resting D. some times D. cleans D. listen D. time D. reach D. home to D. how D. For D. get out D. drinks D. for D. hardly