Упражнение 1. Вставьте а, an или the

This is an apple.
I have a book. The book is interesting.
She wants to be an engineer.
Look at the sky! It's blue.
He has an umbrella. The umbrella is black.
This is an orange. The orange is sweet.
I saw an elephant at the zoo.
The Sun is bright today.
She bought a new dress.
Is this a pencil?