PRACTICE: Fill in the gap with IN/ ON/ AT or Zero. Then explain why.
1. I'll see you ______ next week. (không dùng giới từ trước thành ngữ có NEXT)
2. He was born __IN__ 1991. (IN + Năm)
3. Did you see her ______ today?
4. It starts ______ tomorrow. 
5. It was sunny ______ my birthday. 
6. Frankie started working for her law firm ______ 2015.  
7. What's on the TV ______ midnight?
8. The factory closed ______  June. 
9. ______ the winter, it usually snows. 
10. ______ Friday, she spoke to me. 
11. What are you doing ______ the weekend?
12. Luckily the weather was perfect ______ her wedding day.
13. The anniversary is ______ May 10th. 
14. Where did you go ______ last summer? 
15. The movie starts ______ 20 minutes. 
16. ______ the moment, I'm busy. 
17. They were very popular ______ the 1980s. 
18. My appointment is ______ Thursday morning. 
19. We had the meeting ______ last week. 
20. Are you staying at home ______ Christmas Day?
21. I have to speak to the boss ______ lunchtime. 
22. ______ 8 o'clock, I must leave.
23. There was a loud noise which woke us up ______ midnight.
24. Do you usually eat chocolate eggs ______ Easter?
25. What are you doing ______ the weekend?
26. Last week, I worked until 9pm ______  every night.
27. The plane leaves______ tomorrow morning ______ 8:00 AM. 
28. She plays tennis ______ every Fridays.
29. The trees here are really beautiful ______ the spring.
30. I'll see you ______ Tuesday afternoon then.
31. Shakespeare died ______ 1616.
32. She studies German ______ every day.  
33. Franklin began working on the project ______ yesterday. 
34. In my hometown, the shops open early ______ the morning.
35. She met her husband ______ 1998.
36. The party is ______ next Saturday.
37. We are meeting ______ Friday morning.
38. I often get sleepy ______ the afternoon.
39. His daughter was born ______ the 24th of August.
40. Mobile phones became popular ______ the nineties.
41. Jane is arriving ______ January 26 ______ 2 o'clock ______ the afternoon. 
42. It snows here ______ every year ______ December. We always go outside and play in the snow ______ Christmas day. 
43. Normally, ______ New Year's Eve, it's tradition to kiss the one you love ______  midnight. 
44. Don't be ridiculous; there were no telephones ______ the seventeenth century! The telephone was invented ______ the 1870s. 
45. The hills here are covered with wildflowers early ______ spring. 
46. You should come ______ time. It's impolite to be late.   
47. Could you come ______ Monday morning?   
48. I'm going to do the presentation at their company ______ next week.   
49. They're getting married______ two months.   
50. This beautiful building was built ______ the 16th century.