Part 2: Forget to do vs forget doing - English In A Minute

Take a look at these examples:

'I forgot to lock the door.'

'I forgot locking the door.'

Notice the difference in the way that I said these examples.

When we use the verb 'forget' followed by the infinitive with 'to',

it means that 'you were supposed to do something, but you didn't actually do it.'

So, I was supposed to lock the door, but I didn't.

However, when you we use the verb 'forget' followed by an –ing verb,

it means that 'you did do something, but you have no memory of it'.

So I did lock the door, but I don't recall it.