509. She ____for Beijing tomorrow.

　　 A. is leaving　 B. is going to leave　 C. leaves　 D. leave

508. I ___ with snow by the sea this time last year.

　　 A. played　 B. was playing　 C. had played　 D. has played

507. It ___when I arrived in Beijing.

　　 A. snowed　 B. is snowing　 C. was snowing　 D. had snowed

506. Mary and John ___when the teachers came in.

　 　A. talked　 B. were talking　 C. talk　 D. was talking

505. .Don’t speak while you ____TV.

　　 A. watch　 B. watched　 C. are watching　 D. were watching

504. He _____his homework two hours ago.

　　 A. has done　 B. had done　 C. did　 D. was doing

503. The clock has stopped. At what time _____.

　　 A. did it stop　　 B. has it stopped　 C. does it stop　 D. hadn’t stopped

502. The things talked about in this report ___over a year ago.

A.　 had taken place　 B. took place　 C. have taken place　 D. were taken place

501. I don’t know if he ____, if he ___, I’ll let you know.

　　 A. comes; come　　　　　　　　　 B. will come; will come　

　　 C. comes; will come　　　　　　　 D. will come; comes

500. --- Shall we visit the museum if the rain ____?

　　　 ---Yes, we shall.

　　 A. will stop　 B. has stopped　 C, stopped　 D. stop