I. 1) entered, had prepared; 2) remembered, hadn't locked; 3) arrived, has gone; 4) has read, saw; 5) came, had left; 6) said, had discussed; 7) has begun, came; 8) has taken part; 9) read, had left; 10)hoped, have won;
II. I hadn't a done all my homework by 10 o'clock.
Who had done all the homework by 10 o'clock?
What had I done by 10 o'clock?
When had I done all my homework?
2) He hadn't left Moscow by the end of May.
Who had left Moscow by the end of May?
What had he left by the end of May?
When had he left Moscow?
3) Our students hadn't read many books by the end of the year.
Who had read many books by the end of the year?
How many books had our students read by the end of the year?
What had our students read by the end of the year?
When had our students read many books by the end of the year?