GURUKUL INFORMATICS

If / Unless

Expressing a specific condition for an outcome

 

 

IFUNLESS 

If  introduces a clause with a condition (one of many) to achieve a specific outcome.  The (dependent) clause may be placed before or after the the main (independent) clause.

Unless (if...not)  introduces a (dependent) clause with a condition that is an exception to achieving the outcome in the main clause. 

OUTCOME

You will have a tender turkey.

IF

 if you cook it slowly

OUTCOME

You will have a tender turkey

EXCEPT IF / IF NOT

unless you overcook it.  

You will have a tough turkey.

if you overcook it

You will have a tough turkey

unless you cook it slowly. 

We'll arrive at 8:00. 

 if our train is on time

We'll arrive at 8:00 

unless our train is late.

We'll bring some champagne.

if you wish.

We'll bring some champagne.

unless you object.

 

Emphasis Clause Order
EMPHASIS PLACEMENTSTANDARD PLACEMENT

The if or unless-clause can be placed before the outcome clause for emphasis.  A comma is placed after the first clause.

When the if-clause or unless-clause is placed after the main clause (medially), no particular emphasis is intended. NO COMMA is used.

 If you wish, we'll bring some champagne.

We'll bring some champagne If you wish.
   

Unless you object, we'll bring some champagne.

We'll bring some champagne unless you object.
   

 

 

Tense Use
PRESENT / PASTFUTURE

When discussing habits or routines, the present or the past tense can be used in conditioned statements. See Pres-Past Conditions.

However, when discussing future plans, the present tense is used to refer to the future in the unless-clause or if-clause.

We usually arrive at 8:00 if our train is on time.
We usually arrived at 8:00 if our train was on time.

We will arrive at 8:00 if our train is on time. 
*We will arrive at 8:00 if our train will be on time.  Use present tense instead.

We always arrive at 8:00 unless our train is late. 
We always arrived at 8:00 unless our train was late.
 

We'll arrive at 8:00 unless our train is late. 
*We'll arrive at 8:00 unless our train will be late.   Use present tense instead.

*Yellow highlighting indicates example of incorrect usage.

 

 

Connectors for Condition vs. Outcome
CONDITIONOUTCOME

If / only if / unless / provided that (a conjunction) introduces a clause with a specific condition to achieve an outcome.

Otherwise / or else (if...not)  introduces a clause with a the likely outcome if you do not do the action in the clause or sentence before it.

If you use a thermometer,
This is one way to tell when it's ready. There may be other ways as well.

you will know when your turkey is done.

Only if you use a thermometer,
There is only one way to tell when it's done. (Specifically, use this way.)

will you know when your turkey is done.

Provided that you use a thermometer,
There is only one way to tell when it's done. (Specifically, use this way.)

you will know when your turkey is done.

Unless you use a thermometer,
Not using a thermometer will give bad results. (Listen to me!)

you won't know when your turkey is done.

 

Use a thermometer.

Otherwise, you won't know when your turkey is done. (Introduces an independent clause)

Use a thermometer,

or else you won't know when your turkey is done.
 

Note:  Sometimes, using the negative form is a way for the speaker to impose his/her will. Compare: "Are you tired?" and "Aren't you tired?".  The speaker, when using the negative, wants the listener to agree.