Fill in: can/can't or could/couldn't. When I was younger, I didn't know the first thing about computers. I 1) even turn it on! One day, I saw an ad about free computer courses. In no time, I 2) use a computer like an expert. I liked it so much that I decided to study it at university. Today, I'm a computer programmer and I 3) not only use it, but I actually make new programmes for it. I love computers and I 4) imagine my life without them.
1) couldn't
2) can
3) could
4) can't