19. Every year we build new roads in this region.
20. Someone has spilt some vine on the tablecloth.
21. This music was composed by Beethoven.
22. Pete goes to the South every summer.
23. A new school was being built in our town.
24. I have been waiting for them for 20 minutes.
25. The Earth and other planets rotate around the Sun.
26. Last summer I spent in the South.
27. We shall begin this work tomorrow.
28. The design will be reading in two days.
29. He has been watching TV for two hours.
30. I saw the start of the first space rocket.
31. I should have been working.
32. He said we should finish the work today.
33. They have been called by him.
34. They have been calling him.
35. The work has been finished.
36. They have finished the work.
37. I said I should come soon.
38. She had been painting the picture for some days, when I came.
39. He will have been writing a letter for three hours when you come.
40. He said they would be working in the laboratory from 10 to 12.
41. New material was being explained by the teacher yesterday at 10 o'clock.
42. When I entered the reading-room John was looking through some magazines.
43. He said they would have finished their work by noon.
44. I shall have ironed the dress by 9 o'clock.
45. New material will have been explained by the teacher by the end of the first lesson.
46. Leaving the house yesterday, he said he would come in two hours.
47. He is working on his thesis now.
48. We shall be expecting you at 5.