Unless and If

Often when we are talking about present situations, we use unless instead of if...not.

Unless means except if or simply it means if...not.

Both of these examples have the same meaning and refer to the present time.

"You can't go on vacation unless you save some money."
"If you don't save some money, you can't go on vacation."

"You will feel cold if you don't wear a coat."
"You will feel cold unless you wear a coat."

Unless is good to use when it highlights an exception to what is generally true. In this example I only have one reason why i may be late: traffic (vehicles on the road):

"I'll arrive at 10am unless there is traffic."
"I'll arrive at 10am if there isn't traffic."

This next example shows us that sometimes the context can change and unless is not exactly interchangeable with if...not.

"I'll be annoyed if I do not arrive at 10am." - Being late will annoy me.
"I'll be annoyed unless I arrive at 10am." - The only thing that can stop me from being annoyed is arriving at 10am.

Now let's practice using if...not and unless. Choose the correct form in each sentence:

• 1 - My dog ___ bark unless it is hungry.
  
  won't
  don't
  
  
• 2 - Unless you ___ to go to bed early, we should go out.
  
  want
  wants
  
  
• 3 - ___ you don't slow down, we are going to crash!
  
  If
  Unless
  
  
• 4 - You cannot go into bars ___ you are over 18.
  
  unless
  if
  
  
• 5 - In my country, ___ you cannot speak English, it's hard to get a good job.
  
  if
  unless
  
  
• 6 - She'll fail the exam if she ___ study.
  
  don't
  doesn't
  
  
• 7 - We'll be late ___ we leave soon.
  
  unless
  if
  
  
• 8 - ___ I am not feeling better tomorrow I will go to the doctor's.
  
  Unless
  If
  
  
• 9 - ___ you do not make the payment in time, your car will be confiscated.
  
  Unless
  If
  
  
• 10 - You will lose your job ___ you change your attitude and become friendlier.
  
  if
  unless