What is the difference between these two products?

I have been separated from her for a year.

This is a different problem.

Please tell me the difference between these two products.

He often uses TDN notation to shorten his messages.

Suku is an alternative spelling for cormorant.

We are considering introducing a new voting system.

Learning a new input method is difficult.

We have developed a new methodology to solve this problem.

This accessory is sold separately.