I generally understand that "the" would be used when the subject or object is mentioned again in a sentence to replace the subject or object. For example: He is an office worker. The guy goes to office every day.
Today, I write an email to my teacher telling him: I will follow your instructions in class to improve my math. I am therefore confused whether I need to use "in the class" or "in class".
Another example is: We see the/a possible recession in (the) economy. I am wondering shall we need to use "the" in this sentence.
Thank you for your reply and explaination.