❓'When', 'if' and 'in case' - Improve your English with Learners' Questions

Hi guys! Dan for BBC Learning English here with this week's Learner Question. Find out

what it is after this.

OK! This week's Learner Question comes from Honza from the Czech Republic, who writes:

what is the difference between the use of when and if in all types of conditional sentences?

And Trung from Vietnam, who writes: would you please explain to me the differences in

use between in case and if? It’s a double learner question. you’re getting value for

money now aren’t you? OK, guys – pay attention.

So, we use when for things that are certain to happen in the future. For example, I’ll

give you a ring when I get home from work. Now note that although the time reference

is clearly in the future, we use the present tense in the when clause.

We use if for things that may or may not happen, or that we’re not certain about. For example,

if I decide to come to London this year, I’ll give you a call.

Now in all of these examples we’re talking about future conditions and whether we use

when or if depends upon the certainty of things happening in our opinion. However, when and

if are interchangeable when we’re talking about things in general. And in this case

if can mean whenever. For example, I keep the air-conditioning on at night if, when,

or whenever the temperature goes above 30 degrees. Did you get it?

We use in case to talk about taking precautions. That means doing something because something

else might happen. For example, I’ve brought some candles in case there’s a power cut.

When we use in case, we’re describing possible future situations, but when we use if, we’re

talking about conditions that might apply. Compare the difference: I’ll fill up the

car with petrol in case you need to go to Brighton. That means, I’ll fill up the car

now and you might go later. However, I’ll fill up the car with petrol if you need to

go to Brighton means tell me that you’re going to Brighton and then I’ll fill up

the car.

Honza, Trung I hope that answers your question. Thank you very much for writing to us. If

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it for this week’s Learners’ Questions. I’ll see you next time. Bye!