51. I/ had/ An/ clean/ bedroom/ before/ let/ her/ go out/ play// a. I had An clean up her bedroom before I let her going out to play. b. I had An cleaned her bedroom before letting her go out for playing. c. I had An clean up her bedroom before I let her go out to play. d. I had An to clean her bedroom before letting her go out to play. 52. It/ wonderful/ hear/ magnificent performance// a. It was wonderful to hear such a magnificent performance. b. It was wonderful of hearing a magnificent performance. c. It's wonderful to hear such magnificent performance. d. It will be wonderful to hear a such magnificent performance. 53. He/ not keep/ promise/ visit me/ regularly// a. He doesn't keep promising and visiting me regularly. b. He didn't keep his promise to visit me regularly. c. He hasn't kept to promise to visit me regularly. d. He doesn't keep his promise to visit to me regularly. 54. We/ listen/ old man/ say/ his story/ beginning/ end// a. We listened to the old man saying his story from beginning to end. b. We listened the old man say his story from the beginning to the end. c. We listened to the old man say his story from beginning to end. d. We listened to the old man to say his story from beginning to end. 55. boys/ clever/ see/ solution/ problem/ so quickly// a. The 'boys were clever to see the solution to the problem so quickly. b. Boys are clever to see the solution of problem so quickly. c. The boys are clever at seeing the solution to the problem so quickly. d. The boys were clever to see the solution of the problem so quickly