Question

Which of them is right from the following? 1)the teacher will come in the fourth period. 2)the teacher will come on the fourth period. and kindly type the reason too!

Answer 1

the teacher will come in fourth period. as, the word on is supposed to use when a certain thing is upon anything. for example: the pen is on the table, here we cannot say that the pen is in the table as it is upon the table