As, Since, Because, So

The words as, since and because can be used to refer to the reason for something. So is used to refer to the result.

• It was a pleasant evening. And hence we decided to go out.

We can combine these two sentences into one in the following ways.

• As it was a pleasant evening, we decided to go out.
• We decided to go out because it was a pleasant evening.
• Since it was a pleasant evening, we decided to go out.
• It was a pleasant evening, so we decided to go out.

Notes

Clauses introduced by as and since usually come at the beginning of sentences. As and since-clauses are relatively formal. In a less formal style, we can express the same idea using so.

A because-clause can go either before or after the main clause.

• My brother had refused to accompany me. And hence I went to the court alone.
• As my brother had refused to accompany me, I went to the court alone.
• Since my brother had refused to accompany me, I went to the court alone.
• Because my brother had refused to accompany me, I went to the court alone. OR I went to the court alone because my brother had refused to accompany me.
• My brother had refused to accompany me so I went to the court alone.

Notes

When a subordinate clause comes at the beginning of a sentence, we usually separate it with a comma.