Expressing the reason

We can use several different grammatical structures to show the reason for something. For example, we can express that idea using the coordinating conjunction for.

I was tired after my journey, for I had been driving non-stop for twelve hours.


Although ‘for’ is grammatically correct in the sentence given above, it is rarely used. We are more likely to express the same idea using the subordinating conjunctions because, since or as.

I was tired after my journey because I had been driving non-stop for twelve hours.


As / since I had been driving non-stop for twelve hours, I was tired after my journey.

More examples are given below.

They postponed the meeting because the chairman was ill.

As / since the chairman was ill, they postponed the meeting.

Strictly speaking, for can be used to express the same idea; however, it is mainly used in very formal contexts.

They postponed the meeting for the chairman was ill.


Clauses introduced by as and since usually come at the beginning of the sentence. Because-clauses tend to go after the main clause.

The same idea can also be expressed using the prepositions due to, because of and as a result of.

The meeting was postponed due to / because of the chairman’s illness.


Complete the following sentences using an appropriate conjunction or preposition.

1. ………………… I was ill for several months, I lost my job.

a) because

b) due to

c) because of

2. It is raining again, …………………. we will have to cancel the picnic.

a) as

b) so

c) since

3. I decided to take a break, ………………. I was feeling tired.

a) for

b) because

c) Either could be used here

4. We were late ……………….. it rained.

a) because

b) because of

c) due to

5. The match was cancelled ………………. bad weather.

a) due to

b) because of

c) Either could be used here.


1. because; 2. so; 3. for/because; 4. because; 5. due to / because of