In your interviews for an ESL teacher, you are asked a question of this sort:

What is the difference between:

a. I am taking the bus tomorrow. b. I am going to take the bus tomorrow.

              OR

a. I lived in Kerala for 2 years. b. I used to live in Kerala for 2 years.

Surely, they mean the same thing. That's precisely what makes it difficult to explain the difference. Could anyone help me with it.

In your interviews for an ESL teacher, you are asked a question of this sort:

What is the difference between:

a. I am taking the bus tomorrow. 
b. I am going to take the bus tomorrow.

Or

a. I lived in Kerala for 2 years. 
b. I used to live in Kerala for 2 years.

Surely, they mean the same thing. That's precisely what makes it difficult to explain the difference. Could anyone help me with it?