Question

add a subordinate clause to expand the sentence meaningfully.
1. I know of a sweeper -boy.

Answer 1

I know a boy which is a sweper

Answer 2

The meaningful sentence after expanding the sentence is following – I know a boy who is a sweeper.

Here “who” is used as the subordinate clause.

A subordinate clause can be referred as a clause that is introduced as a conjunction typically in a complex sentence.

The clause can join two sentences and makes it meaningful.

A sub-ordinate clause is dependent on the main clause.