Question

she was only 18 years old when she made her international debut
(underline the subordinate clause)

Answer 1

The subordinate clause here is ‘..when she made her international debut’ as it begins with the subordinating conjunction, ‘when’ and adds extra information to the main clause.

Answer 2

The subordinate clause here is given by ‘..when she made her international debut’.

This is because it begins with the conjunction with subordinating character, ‘when’ provides an extra information to the main or principal clause.

A subordinate clause, also named as a dependent clause, which cannot stand alone in a construction of a sentence because it is an incomplete conception and must have that independent clause with it to function properly.

A clause is nothing but just another word for a group of words which comprise single subject and verb.