Ordinal and cardinal numbers in English

We have breakfast at o'clock. (8)
It is the time he comes here. (8)
I have bought books. (4)
This is the book I am reading this month. (4)
You must do this exercise the time. (2)
I have seen of my friends. (2)
He is in the class. (7)
He has learnt English for years. (7)
I have worked on this for hours. (3)
You will find the answer in the lesson. (3)
Monday is the day of the week. (1)
There is only cake left. (1)
The part will be for him. (10)
of his soldiers were killed in the battle. (10)
is a good number. (5)
My boy is in the form. (5)