1. Unless she works hard, she will fail the exam
2. It's 3 weeks since he last played tennis
3. Because of his illness, he can't finish the work on time
4. Lan can't swim as well as Han
5. His brother hasn't smoked since March/2010
6. This is the first time i have eaten this food
7. The last time Mai phoned her boyfriend was 2 months ago
8. Why didn't you go to class last Monday?
9. George hasn't come to the movie for 2 weeks
10. It's 5 months since i used this beautiful hat
11. This is the most expensive computer he has owned
12. I spend two hours each day doing my homework
