519. They _____here since they arrived here.

A. lived　 B. live　 C. have lived　 D. had lived

518. It ____two days since I ____a cold.

　　 A. is; caught　　 B. was; caught　 C. has been; have caught　 D. is; have caught　

517. He said it _____two years since he ____here.

　　 A. is ;　 came　　 B. was; had come　 C. was; came　 D. had been ; had come

516. ---Where ___the ruler?

　　　 ---- I ___it two weeks ago, but now it is gone.

　　 A. have you seen; saw　　 B. did you see ; have seen　

B.　 had you seen ; saw　　 D. were you seen ; have seen

515. Great changes _____since 1949.

A.　 have taken place　 B. have been taken place　 C. took place　 D. has taken place

514. He ____here for five years.

　　 A. has left　 B. left　 C. has been away from　 D. is leaving　

513. It ___thirty years since he left his hometown.

　　 A. had　 B. has　 C. is　 D. was

512. We____each other since we were little boys.

A.　 know　 B. knew　 C. have known　 D. had known　

511.____writing your composition?

　　 A. Will you finish　 B. Have you finished　 C. Had you finished　 D. Are you finishing

510. He ____chess at nine last Sunday.

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