Question

How can l move the subordinate clause to the beginning of the sentence?

Answer 1

Answer:

?!  This sentence has no subordinate clause. In fact, it lacks a subordinating conjunction.

Explanation:

Do note that it IS possible to rewrite this sentence to CREATE a subordinating clause, but there is no subordinate clause that can be moved -- based on the sentence you have provided.

Some examples:

After clothes become too worn to be sold, they can be shredded and reprocessed into new items.

Whenever clothes become too worn to be sold, they can be shredded and reprocessed into new items.

Once clothes become too worn to be sold, they can be shredded and reprocessed into new items.