A/An or The

It is perhaps useful to study a few pairs of sentences in which only the articles differ to see whether there is a difference in meaning.

• He came and sat down in the armchair. ( i.e. the only armchair in the room.)
• He came and sat down in an armchair.( i.e. in one of several armchairs which were in the room.)

• I’m going to put  these flowers on the table in the hall.(i.e. on the only table there is in the hall.)
• I’m going to put these flowers on a table in the hall.( i.e. on one of the tables which are in the hall.)

• The cat has ruined all my plants.( i.e. reference to a definite cat. The family cat , for example)
• A cut has ruined all my plants.( i.e. there are several cats and we don’t know which one has done it.)

Exercise