Is it easy to learn the conditional mood in English? If only!

After English students learn the four types of conditionals with if-clauses and figure out when to use each one, they are told that there are other words and patterns to indicate the conditional mood, such as unless, even if, and should.

Students often struggle with the conditional should (also called should-inversion) for a few reasons. First, the pattern differs from other conditional patterns, and second, the meaning is unrelated to should as a modal of advice. It is also quite formal, so students don’t come across it all that often.

But much like any grammar target in English, the conditional should can be explained and learned fairly painlessly using patterns and examples.

Meanings

Conditional should and modal should have very different meanings.

Students first learn that should is a modal of advice. The meaning of modal should is a suggestion.

• You should pay attention in class.
  (I suggest that you pay attention in class.)

Conditional should means if and is used for hypothetical situations.

• Should you need anything else, please call this number.
  (If you need anything else, please call this number.)

Patterns

Conditional should and modal should have different patterns in English.

Modal should follows the typical S-V-O sentence pattern:

subject + modal + base verb

Conditional should has inversion in the sentence, which means that the subject and verb are switched. This is confusing for students because although inversion is common in questions, it rarely occurs in sentences.

The pattern of a conditional should sentence is:

modal + subject + base verb

Function	Type	Example
Modal	sentence	She should study for tomorrow’s exam.
	question	Should we study for tomorrow’s exam?
Conditional	sentence	Should you call after hours, leave a message.
	question	Should I happen to call after hours, is it possible to leave a message?

The patterns for conditional if and should are fairly similar, but note that if-clauses follow normal tense conjugation patterns with -s, -ed, etc., whereas conditional should takes a base verb (as modals always do).

Word	Type	Example
If	sentence	If he calls, please answer right away.
	question	If he calls, can you please answer right away?
Should	sentence	Should he call, please answer right away.
	question	Should he call, can you please answer right away?

Examples & Usage

The conditional should is a formal expression that we don’t use in speaking too often. It is more common to see in written form, such as in guidelines or regulations, on signs, or in legal documents.

• Should anything happen, call this number.
• Should the computer lock you out, try resetting the password.
• Should you fail to comply with these regulations, you will be banned from the organization.
• Should we be unable to reach our goal, we will try again next year.

The conditional should is most often used in place of the zero or first conditional. Remind your learners that the zero conditional is used for true facts or repeated actions, and the main clause is formed with a simple present verb. The first conditional is used when an outcome is likely or possible, and the main clause is usually formed with will + base verb.

• If no one answers, please call back tomorrow.
• Should no one answer, please call back tomorrow.
• If I pass the test, I will graduate.
• Should I pass the test, I will graduate.

It is possible, though not common, to use the conditional should in place of the second conditional when an outcome is unlikely or impossible. The main clause is usually formed with would + base verb. Remind students that the verb following conditional should must be a base verb (not a past verb).

• If I were rich, I would travel around the world.
• Should I become rich, I would travel around the world.

Practice

• Conditionals Chart
• First Conditional
• Second Conditional
• Third Conditional