Two simple sentences can be combined into one by using an adverb clause. Note that an adverb clause usually indicates the time, place, manner, purpose or frequency of an action. Adverb clauses can be introduced by the conjunctions as, when, because, while, so, so that, that, if, whether, when, after, before etc.

He looked into the well. He was stunned.

He was stunned when he looked into the well.

She finished her studies. She went abroad.

After she finished her studies she went abroad.

You may go. You have to complete the work.

You may go after you have completed your work.

Here we connect the three sentence pairs using adverb clauses of time. The common conjunctions used to introduce adverb clauses of time are when, before, after, while etc.

She worked hard. She wanted to pass the examination.

She worked hard so that she might pass the examination.

We eat. We may live.

We eat that we may live.

Here we connect the two sentences using an adverb clause of purpose. Adverb clauses of purpose are usually introduced by the subordinating conjunctions so that, so, that etc.

He is poor. He is honest.

Although he is poor he is honest.

Here the subordinating conjunction although shows concession or contrast.

I will come. He must invite me.

I will come if he invites me.

Here the two clauses are combined using an adverb clause of condition.

I could not meet him. He was not at home.

As he was not at home I could not meet him.

She was depressed. She didn’t know what to do.

She was depressed because she didn’t know what to do.

Here the two sentence clauses are combined using adverb clauses of reason. These are usually introduced by the subordinating conjunctions as, because, since, so etc.