Many businesses have key cards instead of the normal metal key to get into rooms or buildings.

In this case, the key card lets me pass through the security gates.

A " card reader" is a machine that electronically " reads" the key card and decides whether a person should be allowed to do something.

The card reader is able to look at the electronic information on the card and determine if I should be let in (if I can go in or not).

We use card readers for many things; when you buy food or groceries with a credit card, in many American supermarkets you have to put your credit card into or through a card reader at the store.

When I put my key card into the card reader at work, the security arm goes up.

A " security arm" is a long, heavy metal or wood bar that blocks a road, but it can be moved up to let people drive by if they have permission. So, it's a kind of security gate.

In the movies, bad people sometimes drive quickly so that their cars will break through the security arms, but in usual life we usually wait for the guard or the machine to lift the security arm and let us drive into the parking lot.

Next I drive into the parking structure.

A " parking structure" is a large concrete building with many floors (or levels) for cars to park on.