Verb tenses exist in order to allow us to specify at what point in time some event occurred – did it happen at one point in the past, or is it still happening? Is it happening now, or will it happen in the future?, etc. Because so many different tenses exist, GMAT questions are often extremely complicated, using several different tenses in a single sentence. The correct tense (or tenses) makes the sequence of actions clear.

Here's an example of a relatively simple verb tense error, and its correction:

Incorrect: After he had finished his performance, he would go to the party.

Correct: After he had finished his performance, he went to the party.

Why is the second sentence correct? Because the order of events is well clarified. Both events - the performance and the party - happened in the past, but the performance happened first, and the party second. Thus both verbs should be in the past tense: "had finished" in past perfect to indicate that this happened first, and then "went" in simple past. The incorrect sentence implies that the performance happened once in the past, but that his after-performance party attendance was ongoing - which doesn't make any sense.

Here's another example.

If the cyclist wins the race, it will be representing an extraordinary comeback from his earlier cancer.

To determine whether this sentence is correct, let's break it down into its constituent parts:

The "if clause" at the beginning of the sentence indicates a hypothetical: a sentence written in if...then... form. This kind of sentence requires that the dependent event be in the simple future tense: meaning that the event, if it happens, will happen once, at some time in the future, following the first event's occurrence. It will not keep happening. Here, however, the dependent event is in the future continuous, not the simple future.

Incorrect: If the cyclist wins the race, it will be representing an extraordinary comeback from his earlier cancer.

Correct: If the cyclist wins the race, it will represent an extraordinary comeback from his earlier cancer.

Why is the second sentence correct? Because a positive outcome of the race, which is as yet undetermined, is only going to "represent his comeback" once – as soon as it happens. The first sentence implies that the cyclist's victory is going to keep representing a comeback for the duration of his victory – which is confusing, and doesn't make much sense.

To help determine whether the verbs in a sentence are in the proper tenses, pick one event as a "base" action, and then try to figure out when other events occurred in relation to that event. Try to discern whether the events occurred prior to the base action, or after the base action; or at the same time as the base event took place. Keep in mind that actions that start before the base may continue after the base.

Ask yourself: "What happened first, second? What makes sense logically?"

This is only half of the process: after you determine when the events took place, you still need to know what verb form corresponds to the time sequence you've identified. This requires a working knowledge of verb tense, as well as of mood and voice - it's very important to study them.

	Tips for recognizing verb tense errors: 1. Watch for –ing forms. Typically, –ing forms are sometimes used as junk answers on the GMAT; you will often be given a better alternative. I am walking I was walking I had been walking 2. Watch for time sequences. Be alert for the appearance of several verbs indicating the occurence of several events that happen (or happened) at different points in time. Pick one verb as the "base" in time sequence, and determine the order of events relative to the base event.

A. Introduction

C. Mood