Tricky Prepositions Part 2
For and Since
For is used with a period of time and can be used with different tenses.
Since is used with a point in time and is used with the present perfect.
- I worked in my last job for five years.
- I am going on holiday for two weeks.
- I have been living here for three months.
- I have been living here since March.
- I have been on holiday since Wednesday.
- I have been waiting since 9:00 am.
By and Until
By is used for an action or event that takes place before a specified deadline. The event or action can take place before the deadline or on the deadline at the latest.
Until is used for an action or event that takes place over a specified period of time. It lasts for the whole of that time.
- Please send me the report by Friday.
- Can you call me by 25 August, so I know what’s going on.
- I’d like you to arrive by 10:00 am, so that we can start the meeting on time
Until (or till)
- The meeting starts at 10:00 am and lasts until lunchtime.
- His contract runs until the end of the year.
- Could you keep checking Sarah’s emails until she gets back from holiday.
Ago and Before
Ago describes how far back in the past something happened.
Before describes when an action or event took place in relation to another action or event.
- She changed her job six weeks ago.
- The situation was a lot worse a year ago.
- I started my current job twenty years ago.
- I always drink a cup of coffee before I start work.
- Can you switch the lights off before you leave the office.
- Can you speak to me before you speak to her.
During and While
Both during and while show parallel actions or events.
During is a preposition so it is followed by a noun, which often represents the action itself.
While is a conjunction so it is used at the start of a complete sentence (or part of a sentence).
- I fell asleep during the presentation.
- During the phone call it became clear to me that my boss was angry.
- I drank too much coffee during the meeting.
- I fell asleep while he was giving his presentation.
- While I was talking to my boss, it became clear to me that he was angry.
- My computer shut down while I was away from my desk.