영어 -st, -nd, -rd 와 -th 쓰임새
The correct one is 12th of February. Tricky it may seem but here is the rule: When a number ends with 1, 2, or 3, the number must be suffixed with “st”, “nd” or “rd” respectively. However, if the number before 1, 2 or 3 is 1, then it must be suffixed with “th.” This might help: 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th, 16th, 17th, 18th, 19th, 20th, 21st, 22..