Question

______ the staff he read the address​

Answer 1

Calling the staff he read the address.

Answer 2

Answer:

You have not mentioned which part of speech is to be used in the blank.

If this question is from the exercise of, 'Conjunction' then the answer would be:

Before the staff he read the address.

This states that an address was read out before the staff by someone. It makes complete sense

If this question is from the exercise of, 'Preposition' then the answer would be:

To the staff he read the address.

This states that only the staff was there to whom the address was read and not to anybody else. The staff is informed about an address in particular. Hence it makes complete sense and a sentence is one which should make complete sense.