Adverbial clauses

Adverbial clause (used to express time, conditional, purpose/reason, result, contrast, manner)

 This type of clause fills the adverbial slot in a sentence.

Finite adverbial clauses (clauses containing a finite form of the verb) will use a conjunction.

 The road flooded as it rained.

When she laughed, everyone was surprised.

She looked round because she heard the noise.

If you are attending, please let us know.

Non-finite adverbial clauses will use an infinitive form of the verb or present/past participles used without auxiliary verbs. 

To bake the perfect cake, you need excellent ingredients.

The beacon will shine to warn any travellers.

Singing like angels, the choir sounded heavenly.

The dog trembled, frightened by the thunder.

If the subordinate clause starts the sentence, a comma is required to demarcate the two clauses.  If the main clause starts the sentence, the comma is optional.  You should consider whether it is needed to aid clarity and sense for your reader.

As can be seen above, adverbial clauses can start a sentence or be placed in final position.  They can also be embedded, in which case they should be contained within commas.  If this additional information is removed, the sentence will still make sense.

She could, when she put her mind to it, do well in most things.

The dog, frightened by the thunder, trembled.