The GMAT sentence corrections are notorious for testing the usage of the subjunctive mood, a rarely understood verb mood in English. Note that the subjunctive is a mood, not a tense, meaning that it does not have much to do with time. In general, the subjunctive is used to express what is imagined or wished. Let’s distinguish between the three verbal moods by examining one simple sentence: You are at the supermarket.
Indicative: You are at the supermarket
Imperative: Be at the supermarket (in five minutes).
Subjunctive: I wish that you were at the supermarket.
Most of the verbs we use are indicative. The indicative mood is used to express facts or ideas which do not need qualification. The imperative mood is the command. When I tell you to do something (e. g. stop it!), I’m using the imperative mood. The subjunctive, though, expresses the writer’s particular belief about the verb being used. In the sentence above, “you” are not at the supermarket; rather, I’m expressing a feeling about the possibility of your being at the supermarket. There are two situations in which the subjunctive is used:
Hypothetical: Conditional situations using “if” (e. g. If I were you…).
Command: Requests and wishes using “that” (e. g. I wish that you were here).
The hypothetical subjunctive, which often uses “if” or “as though,” indicates conditions that are not likely to happen.
Example: The skilled swimmer glided through the sea as though he were a dolphin.
Clearly, the swimmer is not a dolphin, but he swims as though he were one. To conjugate hypothetical subjunctives, you just use the simple past form of the verb, except in the case of ‘to be’ verbs. For “to be” verbs, always use “were.” Because this is such an usual rule, the GMAT will generally test the usage of “to be” verbs in the hypothetical subjunctive.
Because it is more common to make mistakes with the command subjunctive, it is more common on the GMAT. The command subjunctive is used with certain verbs, like “require,” that indicate a command without using the imperative mood.
Example: My boss requires that you be at work by 6 a. m.
Example: The manager insisted that John stay until sundown.
Notice that you do not conjugate the command subjunctive in the same way that you would conjugate the hypothetical subjunctive. Verbs in the command subjunctive should be conjugated like verbs in the imperative. Notice that if we changed the above examples into the imperative mood, the verbs remain the same:
Example: Be at work by 6 a. m.
Example: Stay until sundown, John.