My brother has two computers: a PC and a laptop. ___ PC is quite old but ____ laptop is brand new.
My brother has two computers: a PC and a laptop. ___ PC is quite old but ____ laptop is brand new.
Explanation
My brother has two computers: a PC and a laptop. The PC is quite old but the laptop is brand new.
Note: Use "A" or "An" to talk about a person or thing unknown to your listener.
Note: Use "The" to talk about a person known to your listener.