Cause and effect sentences show a clear, direct relationship between events. They show how one event or action triggers an outcome. They may also show how an effect has more than one cause, or a cause has more than one effect.

Linking words of cause and result

1. Linking words of cause and result

The linking words of cause introduce a sentence that tells

the cause or reason why an action occurs. The linking words of result introduce a sentence that expresses the consequence or effect of the cause.

2. Different linking words of cause

Conjunctions followed by a complete sentence:
- Because: it usually follows the main clause: Everybody likes her because she's very kind and friendly.
- As and since are very similar. As is less formal than since. They are used when the reason is well known. The clauses that start with these words often begin the sentence:
  As I was very tired, I went to bed early.
  Since you are not interested, I won't tell you about it.
  (As and since can also be used as time connectors).
- For suggests that the reason is given as an afterthought. For-clauses never come at the beginning of the sentence. For is mainly used in literary texts, therefore, it is very formal.
  We listened eagerly, for he brought news of our families.

Connectors followed by a noun, a noun phrase, a pronoun or a gerund:
- Because of: They have had problems raising cash because of the credit crunch.
- Due to and owing to are considered by many speakers as exact equivalents, but this is not so, because due to is adjectival (it follows a noun or pronoun), whereas owing to is adverbial (it complements a verb). Compare these examples:
  The game was cancelled owing to torrential rain.
  The cancellation of the game was due to torrential rain.
  If you are doubtful as to which of these you can use, here's a trick: try to substitute due to with “caused by” and see if it works. *The game was cancelled caused by torrential rain.* doesn't sound correct, so it's not possible to use due to in this case. On the other hand, The cancellation of the game was caused by torrential rain, sounds fine.
  Owing to is interchangeable with because of: The game was cancelled because of torrential rain.
- On account of: The nurse had to keep the baby in another room on account of my illness.
- Thanks to suggests that there is some cause for gratitude, though it can be used sarcastically. She was given a scholarship thanks to her excellent grades.

3. Different linking words of consequence or effect

Thus (very formal): He was the eldest son, and thus, heir to the title.

Therefore (formal, used mainly in written English): She is only seventeen and therefore not eligible to vote.
As a result: There has been a rise in the number of accidents. As a result, the government has decided to lower the speed limit.
As a result of the rise in the number of accidents, the government...
As a result of is followed by a noun, pronoun or gerund. Can you rewrite the previous example using as a result of?
So (less formal): There was nothing on TV, so I decided to go to bed.
That's why: Cold temperatures kill mosquitos. That's why you won't see them in winter.
For this reason: The Colonel was confident that war was impending, and for this reason he hurried his preparations to leave the country.
Consequently (used especially in written English): This poses a threat to the food chain, and consequently to human health.