unless vs. if

hi every one
what is the different between unless and if in zero condition?
thank

First of all, please note the difference between ‘difference’ and ‘different’. As for your question, it has been discussed here: If and unless[YSaerTTEW443543]

TOEIC short conversations: Helping a colleague[YSaerTTEW443543]

Hi Issa4,

A so-called ‘zero conditional’ with ‘if’ typically tells us a condition in which something is always true:

- If someone tells Mary a joke, she always laughs.

You might say that ‘unless’ in a zero conditional tells us a condition in which something is always not true:

- Jane always has a smile on her face unless she has a headache.
The sentence above basically means the same thing as this:
- If Jane has a headache, she does not smile.

[color=darkblue]________________________________________________
[size=75]“You never achieve success unless you like what you are doing.” ~ Dale Carnegie[/size]

Hi Esl_Expert
Thank you for reply on my message.

I can said
unless I have headache, I smile…