Grammatical mood allows speakers and writers to express their attitudes toward what they are saying (for example, whether it is intended as a statement of fact, of desire, or of command). In English, there are many grammatical moods, but by far the most common are the indicative, the imperative, the subjunctive, and the conditional.

You can change tense and aspect of a verb by changing something about the verb itself: For example, to make the verb "enjoy" past tense, you add -ed to the end. In English, mood is a little different. You don't change anything about the verb itself. Instead, you change the sentence structure to express a certain mood.

The Indicative Mood

In English, the indicative mood is the most commonly used. It is used to express factual statements. 

• Atlanta is the capital of Georgia.
• Penguins cannot fly.
• Jebediah likes the beach. 

The Imperative Mood

The imperative mood expresses direct commands, prohibitions, and requests. In other words, it is used to tell someone to do something. In the imperative mood, the subject is almost always implied to be "you."

• Do your homework now.
• Please don't leave your bag there.

However, sometimes the subject can be implied to be "we."

• Let's go!

Let's go

The imperative mood expresses direct commands and prohibitions. 

The Subjunctive Mood

The subjunctive mood is not commonly used in English. It is used for discussing imaginary or hypothetical events and situations, expressing opinions or emotions, or making polite requests. Usually, the subjunctive mood is used in a dependent clause. Subjunctive sentences are often of the following form: [Indicative verb phrase setting up a hypothetical scenario such as "I wish," "I believe," "I hope"] + [Subjunctive phrase describing hypothetical scenario].

• I wish Paul would eat more healthfully. [Main clause "I wish" is factual and in indicative mood; dependent clause "Paul would eat" is hypothetical and in subjunctive mood.]
• I suggest that we wait until after dinner to eat the cake. [Main clause "I suggest" is factual and in indicative mood; dependent clause "we wait until" is hypothetical and in subjunctive mood.]

The Conditional Mood

The conditional mood is used for speaking of an event whose completion depends on another event. In English, the conditional mood is usually of the form "would" + bare verb with no tense or aspect markers.

• I would go swimming if it weren't so rainy.
• He would bake more often if he had a better oven.