First class ( one week days ago ) Second class ( yesterday ) Third class ( now ; at the present time )
We can mention the second class by saying " last session " but how can we mention the first class? We can say this sentence about the second class :
As I recall, the teacher wrote something on the board last session
But How can we talk about the first class in this sentence ( we are not allowed to say " during the first class " as the answer ) :
As I recall, the teacher wrote something on the board ___________ .