reason

The preposition for is used both before and after reason.

• I need to talk to you for two reasons.
• What’s the real reason for your depression? (not … reason of your depression?)

Reason can be followed by a clause beginning why … or that … .

• The reason why I came here was to be with my family.
• Do you know the reason that they’re closing the factory?

In an informal style, why/that is often left out.

• The reason she doesn’t like me is that I make her nervous.

Some people consider it incorrect to use a because-clause as a complement after reason (as in Sorry I’m late – the reason is because I overslept).