Use of by prepositions with examples

We use by meaning ‘not later than’ to refer to arrangements and deadlines:

They said that the plumber would be here by Monday.

The postman is always here by 11 am.

We use by the time, meaning ‘when’, to connect an action that has happened or will have happened before a second action.

The action that happened second comes after by the time:

By the time[action 2]you wake up, [action 1] I’ll have finished work! (When you wake up, I will have finished work)

Not: By the time you will wake up …

Unfortunately the man had died by the time the ambulance arrived. (When the ambulance arrived, the man had already died.)

When we use the passive voice, we can use a phrase with by to say who did the action:

The new street was opened by the Mayor.

The wedding cake was made by Henry’s mother.

We use by + -ing form to describe how to do something:

By pressing this button, you turn on the alarm system.

Then by entering the code 0089, you can turn it off again.

We use by

how to use run by in a sentence

how to use by definition in a sentence