The prepositions of time: until, before, after, and by are essential for indicating when events happen in relation to one another. They help clarify time relationships in sentences.
Until can function as both a preposition and conjunction. It acts as a preposition when it indicates a time or point at which something will happen (e.g., We will wait until noon.). However, when it connects two clauses, it serves as a conjunction (e.g., I will stay here until you return.). It is often abbreviated to till or ’til in informal language.
Examples
The coffee shop is open until 11 AM on weekends.
I will be working until 5 PM.
We played chess until midnight.
We can’t go out until the rain stops..
She’ll be staying in London until the end of the month.
Please wait here until the doctor calls your name.
We often use "from .... until" to indicate when something starts and when it ends.
Examples
The coffee shop is open from 8 AM until 11 AM on weekends*.
The coffee shop is open from 7 AM until 8 PM on weekdays.
I’ll be on holiday from July 1st until July 10th.
We had a party from dusk until dawn.
The school will be closed from the middle of December until the end of January.
We use the preposition before to introduce an action or event happening later than another action. For example, in the sentence “Before you go out, make sure to close the window.”, the action of going out is happening later than the action of closing the window. First, you close the window, then you go out. We also use the preposition before to introduce a time reference before which an action or event happens.
We use the preposition after to introduce an event or action happening earlier than another event or action. For example, in the sentence “I took a long nap after running a marathon yesterday.”, the action “running a marathon” happens earlier than “taking a nap”. First, you run a marathon, then you take a long nap. We also use the preposition after to introduce a time reference after which an action or event happens.
The preposition "by" means not later than.For example, the sentence “I need to send a report by July 22nd.” means that the report must be sent before July 22nd or on July 22nd at the latest.
