I. 1/ a, 2/a, 3/c,4/a, 5/a, 7/c, 8/a, 9/b, 10/c; II. 1/ - , - ; 2/a, -, a, -, a; 3/ - ; 4/ a, - ; 5/a,-; 6/-, a, - ; 7/ an; 8/a, the; 9/-, the, the; 10/a,the,-, - . III. 1/ came, had cooked; 2/ returned, had done; 3/ entered, had opened; 4/had given, bought; 5/showed, had drown; 6/ gave; had brought; 7/saw, had not washed; 8/understood, had not done; 9/knew, had not come yet;10/had returned; 11/returned; 12/had finished; 13/finished; 14/thought, had lost; 15/told, had seen; 16/woke up, had gone; 17/thought, had not come; 18/told , had cooked; 19/had found, lost; 20/came, had left.
1. When I came home, mother had already cooked dinner. 2. When father returned from work, we had already done our homework. 3. When the teacher entered the classroom, the pupils had already opened their books. 4. Kate gave me the book which she had bought the day before. 5. Nick shown the teacher the picture which he had drawn. 6. The boy gave the goats the grass which he had brought from the field. 7. Mother saw that Nick hadn't washed his hands. 8. The teacher understood that Lena hadn't done her homework. 9. I knew that my friend hadn't come. 10. Tom returned from the cinema at five o'clock. 11. Tom had returned from the cinema by five o'clock. 12. I finished my homework at seven o'clock. 13. I had finished my homework by seven o'clock. 14. He though that he had lost the money. 15. Ann told me that she had seen an interesting film. 16. When I woke up yesterday, father had already gone to work. 17. Nick thought that his father hadn't come home yet. 18. Mary told us that she had cooked a good dinner. 19. Yesterday I found the book which I had lost in summer. 20. When we came to the station, the train had already left.
Sit - Sat
Swim - Swam