Ответ:
9. James hasn't arrived at school yet.
10. William has studied a lot of new things since last year.
11. I'm worried because Julie never was absent before.
12. Did you do your homework last night?
13. We've had already three maths lessons this week.
14. The tacher took the register for the first time with his new class last week.
15. The good news is that nobody has failed a test in this class since the beginning of the year.
16. The bus has been late again this morning.
17. William went to university last year after passing all his exams.
18. The teacher hasn't told us about the test untill today.
19. You hasn't done your homework for three week.
20. Have you read this book yet?