It's important that children understand what a clause is because it's one of the building blocks of written English.An clause example is: The fast, red squirrel darted up a tree. The subject of this clause is the fast, red squirrel, and the verb is 'darted'. This can also be called a simple sentence.
A conjunction is a word, or words, used to connect two clauses together. Words such as: 'although', 'because' or 'when' . A subordinating conjunction is simply the word/words that is used to join a subordinating clause to another clause or sentence.