My computer is working correctly.
My computer is not working correctly.

The USB cable is broken.
The USB cable is not broken.

You must download that file.
You must not download that file.

This laptop has got a virus.
This laptop has not got a virus.
______________________________

We use the Internet for our school projects.
We do not use the Internet for our school projects.

He knows how to install the program.
He does not know how to install the program.

My sister designs web pages.
My sister does not design web pages.

I installed this program last month.
I did not install this program last month.

We have to configure the network access.
We do not have to configure the network access.

My computer broke down on Tuesday.
My computer did not break down on Tuesday.

______________________________

This sound card costs £ 99.
This sound card does not cost £ 99.

This wireless mouse cost £ 39.
This wireless mouse did not cost £ 39.

These wireless keyboards cost £ 59 a month ago.
These wireless keyboards did not cost £ 59 a month ago.

These scanners are on offer. They cost £ 129.
These scanners are not on offer. They do not cost £ 129.

These graphic cards tend to cost around £ 49.
These graphic cards do not tend to cost around £ 49.