1. “by” + place: The meaning is " beside “, at the side of, next to, close to

Example: The house is by a river.

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2. “by” + method of transport: This structure describes how you travel somewhere.

Example: Dinesh went to Manipur by train.

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3. “by” + method of communication: This structure describes how you communicate with someone.

Example: I spoke to her by email.

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4. “by” + method of payment: This structure describes how you pay for something.

Example: We paid for the laptop by cheque.

5. “by” and the passive: In the passive voice, “by” indicates who is doing the action. 

Example: The book was written by me. (Passive voice)

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6. “by” + reflexive pronoun: by + myself / yourself

Example: I enjoy staying by myself.

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7. “by” + time expression: The meaning of this structure is not later than; before or at a particular time. We use this structure for deadlines.

Example: Please vacate the room by 11 am.

8. “by” + -ing verb: This structure describes how to do something. It gives us more information about how to achieve a particular result.

Example: How can I turn on the radio? By switching in the main switch