First ( 1st) first

Second second

the third time

the fourth time

Fifth session

Sixth session

Seventh session

The eighth (eighth)

Ninth session

Tenth (10)

Eleventh session (1 1 session)

Twelfth (12) Twelfth

Thirteenth session (13)

14th session (14th session)

Fifteenth (15) Fifteenth

16th (16th) 16th

Seventeenth (17) Seventeenth

18th session (18th session)

Nineteenth (19) Nineteenth

Twentieth (twentieth)

Syntactic function

Ordinal numbers can be used as subject, object, attribute and predicative in sentences.

The second one is what I really need. The second one is what I really need. (as subject)

He chose the second option. He chose the second one. (as an object)

We will carry out the first plan .. We will carry out the first plan. (as an attribute)

Refer to the above content: Baidu Encyclopedia-Ordinal Number