6.

1)a/an

2)the

3)a/an

4)the

5)the

7.

2)a, the

3)a, the

4)an, the

5)an, the

6)a, the

8.

2)a present-the present

3)in the office-in an office

4)bike is old- the bike is old

5)a table- the table

6)a black one-the black one

7)the salt-a salt