Article a, an

1. Article a

1.1. Example

1.1.1. a Book

1.1.1.1. a Clock

1.1.2. a Pig

1.1.2.1. a Heart

1.1.3. a truck

1.1.3.1. a Focus

2. Article an

2.1. Example

2.1.1. an Apple

2.1.1.1. an umbrella

2.1.2. an Orange

2.1.2.1. an iguana

2.1.3. An elephant

2.1.3.1. an Egg