The abbreviations of ordinal numbers in 1-31 are as follows:
1-1: 1st, 2nd, 3rd, 4th, 5th,? 6th, 7th, 8th, 9th, 1th
11-2: 11th, 12th, 13th, 14th, 15th, 16th, 17th, 18th, 19th, 2th
21-31: 21st, 23rd, 231st.
The second is what I really need. The second one is what I really need.
he chooses the second. He chose the second one.
We are to carry out the first plan. We will carry out the first plan.
She is the second in our class. She is the second in our class. (as a predicative)
Note: When ordinal numbers uses it, he usually adds the definite article the; But if the indefinite article A or an appears before ordinal numbers, it means "again" and "again".
We'll go over it a second time. Let's read it again.
We've tried it three times．Must we try it a fourth time? We have tried it three times. Do we have to try it again (the fourth time)?
Extended information:
Rules for the use of English numerals:
1. Publishers in Britain and the United States follow a principle when typesetting, that is, 1 to 1 are represented by words, and numbers above 1 are represented by Arabic numerals (some of them take 1 as the boundary).
eg. that table measures ten feet by five.-The working head is 1 feet long and 5 feet wide.
second, it is more concise to express the number of people in Arabic numerals, but it is more appropriate to express the indefinite number and approximate value in words.
eg.there are 23817 voters on the electoral rolls.
There are 23817 voters on the electoral list.
3. Date, percentage, and special numbers with units, usually Arabic numerals.
eg.maximum swing of table is l2.
the maximum rotation angle of the workbench is 12 degrees.
4. Numbers appear frequently in scientific and technological articles, and it is more advantageous to use Arabic numerals than words to state them.
eg. The new engine has a capacity of 4.3 literes and a power output of 153 kilowatts at 44 revolutions per minute.
This new engine has a volume of 4.3 liters, and its speed is 44 revolutions per minute, and its output power is 153 kilowatts.