Everything English

There are three types of “if” clauses – or “conditionals”. Conditionals present conditions under which certain things are possible, to varying degrees.

One class of “if” clauses sets up conditions that are relatively likely to be realized:

• If James takes a nap, he’ll have the energy he needs to run a mile. (where “he’ll” = “he will”)
• If Karen studies the material, she may pass the test.
• If Dr. Knight listens to the opinions of his colleagues, he will be better informed about the debate over the change in policy.

The active voice (“takes”, “studies”, “listens”) provides an immediacy that suggests that in the real world, there is a real chance that each of the people above will do each of the things mentioned.

The second class of “if” clauses sets up conditions that are less likely to be realized. The situations presented are more hypothetical “what ifs”:

• If James took a nap, he’d have the energy he needs to run a mile. (where “he’d” = “he would”)
• If Karen studied the material, she might pass the test.
• If Dr. Knight listened to the opinions of his colleagues, he would be better informed about the debate over the change in policy.

There’s no easy, rule-based or grammatical way to explain the difference between the two sets of sentences, but it helps to note that the second set presents possibilities in a way that is more speculative. The element of passivity (“took”, “studied”, “listened”) in the second set affords less immediacy that the element of activity (“takes”, “studies”, “listens”) in the first set and so makes the possibility of the events specified actually occurring seem less remote.

Note that there’s another way of expressing the same conditions:

• If James were to take a nap, he’d have the energy he needs to run a mile.
• If Karen were to study the material, she might pass the test.
• If Dr. Knight were to listen to the opinions of his colleagues, he would be better informed about the debate over the change in policy.

This is the subjunctive form, and it might seem counterintuitive at times. It is appropriate, for example, to say, “if I were to” but not “if I was to”, even though “I” is typically paired with “was” when “I” is the subject and the verb “to be” follows in the past tense (e.g. “I was thinking …”). They key here is to remember the construction, “If [someone] were to [do something]… [that someone] might/would/could [be/do something else].”

The last set of “if” clauses presents conditions that are presently impossible to fulfill but if fulfilled in the past would have led to particular results:

• If James had taken a tap, he would have had the energy he needed to run a mile.
• If Karen had studied the material, she might have passed the test.
• If Dr. Knight had listened to the opinions of his colleagues, he would have been better informed about the debate over the change in policy.

Note the use of the past perfect tense (“had taken”, “had studied”, “had listened” and “would have had”, “would have passed”, “would have been”). In these scenarios, the opportunities presented (to take a nap, to study the material, to listen to the opinions of colleagues) have passed, but had the people specified done the things noted, the outcomes listed would have occurred.