15."Diana is a wonderful ballet dancer". "She_____ since she was four". a. has been dancing b. has been danced c. is dancing d. was danced 16."Those eggs of different colors are very artistic". "Yes, they_____ in Russia". a. were painted b. were paint c. were painting d. painted 17. Gold_____ in California in the nineteenth century. a. was discovered b. has been discovered c. was discover d. they discovered 18. All planes_____ before departure. a. will checked b. will has checked c. will be checked d. will been checked 19. I wanted_____ by the head of the company, but it was impossible. a. to see b. to be seen c. seeing d. being to see 20. Katherine_____ at Bob's house every night this week. a. has been eaten b. has eating c. is being eating d. has been eating