BY

MEANS

Means is expressed by a prepositional phrase introduced by 'by':

• I usually go to work by bus
• We managed to sell the house by advertising it in the paper

Sometimes a phrase of means is replaced by a different type of prepositional phrase, eg one of place:

• How did he get in?
  He came in through the window (more usual than by the window)
  
• How did you hear the news?
  I heard it on the radio //They send the message by radio.

Sometimes, when the actor is not mentioned, the instrument or means takes the position of a subject, i.e. the role of the causer of the action:

• They brought the supplies by train > The train brought the supplies.

The article is omitted in by-phrases denoting communication: by car, by train, by letter, by post, by radio, etc.

• travel by bike > ride on the bicycle
• come by bus > sit in the bus
• leave by car> sleep in the car
• come by boat/ship > disembark from the ship
• travel by plane > to board the plane
• go by train > to catch the train

By + gerundive

TIME

By day/night = during the day/ night with some activities:
• we travelled by night

By refers to the time at which the result of an event is in existence:

• By Friday I was exhausted (I became exhausted bfore Friday, I was still exhausted on Friday)
• Please send me the tickets by next week (I want to have the ticket no later than next week)

POSITION

By/beside= at the side of, but it cal also indicate the nearness of one object to another

• She sat in a chair by the door (near)

• The man is standing By/beside the car

• We drove past/by the town hall

AGENT

Subject active verb object
Subject passive verb Agent

• Many critics disliked the play
• The play was disliked by many critics

About 4 out of 5 English passive clauses have no agent. Passive is usually associated with impersonal style (scientific or official writing) where the question of who is the agent is unimportant and often irrelevant:

• The police officer was killed last night
• The question will be discussed at the meeting tomorrow.

• introduction by > the book is introduced by