B2 grammarPart 1 of 3

Prepositions of Time: Deadlines, Duration and Timing

At B2, the challenge is not naming time. It is showing whether an action continues, finishes before a deadline, fills a period or prevents a problem.

12-15 minutes4 guided tasks8-question mastery check

What you will be able to do

UnderstandSeparate deadlines from continuing actions.

ChooseChoose accurately between for, during, in and within.

UseDescribe punctuality and final stages with natural fixed phrases.

Start with the meaning

Is Friday the deadline, or does the action continue until Friday? Predict each answer, then open the explanation.

1. Please send the revised proposal by Friday. Can it arrive on Thursday?

Yes. By Friday means no later than Friday. Thursday is before the deadline.

2. We kept the offer open until Friday. Was it open throughout Thursday?

Yes. Until Friday describes a situation continuing up to that end point.

The essential distinctions

By marks a deadline

Use by for the latest acceptable time. The action can happen earlier. Use until when an action or state continues up to an end point.

Finish it by six. · I will be working until six.

For measures, during locates

Use for with a length of time. Use during with an event or named period. Use while before a clause.

We spoke for an hour · during the meeting · while we were waiting.

In and within set different limits

In two hours can mean after two hours or the time needed. Within two hours means before two hours have passed.

I will call you in two hours. · Reply within two hours.

See the contrast

Choice	Meaning test	Example
by	no later than	Submit the form by 5 p.m.
until	continues up to	The office stays open until 5 p.m.
for	how long?	She worked there for six months.
during	inside which event or period?	No phones during the interview.
on time	at the scheduled time	The train left on time.
in time	early enough to prevent a problem	We arrived in time to board.

A three-step decision tool

Name the time ideaIs it a deadline, an end point, a duration or an event?

Check the actionDoes it continue, or only need to happen once before a limit?

ParaphraseTry “no later than”, “up to” or “early enough”. The right choice often becomes obvious.

Three traps to avoid

✕ I stayed at work by nine.

✓ I stayed at work until nine.

Staying is a continuing situation, so use until.

✕ We talked during three hours.

✓ We talked for three hours.

Three hours is a duration, not the name of an event.

✕ The bus arrived in time at 8:00.

✓ The bus arrived on time at 8:00.

Use on time for a published or agreed schedule.

Guided practice

Say your answer aloud before opening the explanation.

1. The application must reach us ___ 30 September.

by, because 30 September is the final acceptable date.

2. The roads were quiet ___ the public holiday.

during, because the public holiday is a named period.

3. We waited ___ the rain had stopped.

until, because the waiting continued to that end point.

4. Please report any damage ___ 24 hours.

within, because the report must happen before the 24-hour limit expires.