‘Because of’ is a two-word preposition and it is followed by a noun or a pronoun:
Our lives have changed a lot because of new technology.
‘Because’ is a conjuction and it is followed by a clause:
Our lives have changed a lot because we use new technology.
Because of, for or by?
We use because of + noun to show the cause of a situation or event. In the same way, we can use ‘owing to‘ and ‘due to‘
They were delayed because of/ owing to/ due to bad weather.
!!! We can use ‘due to‘ but not ‘because of’ or ‘owing to’ after the verb to be:
His wealth is due to his lottery win.
We use for + noun to introduce an explanation for our behaviour:
I’d like to thank you for the time you gave me.
We use by + noun in a passive construction to show the agent or cause of an action:
We were misled by your advertisement.
Now try the following exercise (solution below):
1. The firm closed down last mont for/ because of financial problems.
2. Because/ Because of the money I earn, I’m able to help others.
3. John is feeling stressed for /because of his hectic job.
4. I’m not happy with the tour for/ because of two reasons.
5. The garden furniture was destroyed by /because of pouring rain.
6. You were recommended because/ because of you offer top-quality service.
SOLUTION: 1. because of / 2. Because of / 3. because of / 4. for / 5. by / 6. because
(Source: Common mistakes at CAE. Cambridge)