I'm going to quote some things about the Greek. We don't call the "indicative" by that name in English, although we certainly have the
subjective, [subjunctive - thanks but no thanks, spell check!] which is something that is a dependent clause, and can't stand alone. Indicative in English basically means it is stating facts. Subjective technically is stating possibilities, conjectures, "what if."
"Just like Greek nouns, the Greek verb also changes form (the Greek 'spelling', so to speak). The form changes based upon the subject of the verb and the kind of action indicated. As was mentioned earlier, Greek is a fully "inflected language." Each Greek word actually changes form (inflection) based upon the role that it plays in the sentence. The stem of the verb shows the basic meaning or action of the word, but the ending (or ‘suffix’) changes to show various details. Not only the ending of the verb may change, but the verb form may have a ‘prefix’ added to the beginning of the verbal stem. Sometimes the actual stem of the verb may change or may add an ‘infix’ to indicate certain other details."
The aspect of the grammatical "mood" of a verb has to do with the statement's relationship to reality. In broad terms, mood deals with the fact of whether the asserted statement is actual or if there is only the possibility of its actual occurrence. "Whether the verbal idea is objectively a fact or not is not the point: mood represents the way in which the matter is conceived" (Dana & Mantey). If the one asserting the sentence states it as actual, then the mood reflects this, regardless of whether the statement is true or false.
The indicative mood is the only mood conceived of as actual while with the other three moods (imperative, subjunctive, and optative) the action is only thought of as possible or potential.
Indicative Mood
The indicative mood is a statement of fact or an actual occurrence from the writer's or speaker's perspective. Even if the writer is lying, he may state the action as if it is a fact, and thus the verb would be in the indicative mood. It may be action occurring in past, present, or future time. This 'statement of fact' can even be made with a negative adverb modifying the verb (see the second example).
This is in contrast to one of the other moods (see below) in which the writer/speaker may desire or ask for the action to take place.
For example: "And they overcame him by the blood of the Lamb."
Rev. 12:11 "God is not mocked." Gal. 6:7
Imperative Mood
The imperative mood is a command or instruction given to the hearer, charging the hearer to carry out or perform a certain action.
For example: "Flee youthful lusts." 2 Tim. 2:22
Subjunctive Mood
The subjunctive mood indicates probability or objective possibility. The action of the verb will possibly happen, depending on certain objective factors or circumstances. It is oftentimes used in conditional statements (i.e. 'If...then...' clauses) or in purpose clauses. However if the subjunctive mood is used in a purpose or result clause, then the action should not be thought of as a possible result, but should be viewed as a definite outcome that will happen as a result of another stated action.
For example: "Let us come forward to the Holy of Holies with a true heart in full assurance of faith." Heb 10:23
"In order that now the manifold wisdom of God might be made known through the church..." Eph 3:10
Optative Mood
The optative is the mood of possibility, removed even further than the subjunctive mood from something conceived of as actual. Often it is used to convey a wish or hope for a certain action to occur.
For example: "And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ." I Thess 5:23
Greek Verbs (Shorter Definitions)
We do have the imperative in English, commonly called the "command" tense. However, unlike Greek and German, or French and Spanish, there are not different, unique words for it in English. For example, if you want someone to stop now, you would just say "STOP!" The exclamation mark, the lack of a subject indicate imperative. Other languages are much more definitive in their verbs.
Same with subjunctive verbs. In Greek, the vowel is lengthened in the subjective, although the ending are similar to the Indicative mood. In English we tend to identify the subjunctive because of the relative pronoun or subordinate pronoun that starts the clause, and that it cannot stand alone.
"I went to the store, which I hoped was open."
"I went to the store," is the main or coordinate clause, and it can stand alone. It is a complete sentence or thought.
"which I hoped was open," is the subjunctive or dependent clause. It starts with a relative pronoun, and it is not complete. It cannot stand on its own.
Greek is very similar, except besides the relative pronoun, it has a verb in the subjunctive. Plus, because of the flexibility of Greek, it can appear in strange places. In English, the subordinate clause is usually, but not always, second. In Greek, there is never a doubt, because of the double identification of the clause with both the relative pronoun and the lengthened verb indicating the subordinate.
Of course, English can be difficult for some to identify the subordinate clause. I always remember my grade 7 English teacher teaching subordinate clauses for literally months. After a few weeks of getting 100% on every daily quiz on this topic, my best friend and I got permission to go to the library and do some research projects. That was very unusual in those days, for a teacher to let someone out of the instruction part of the class. But wisely, she knew we got the idea, and that we were bored to tears. Really, I never understood why the topic was so difficult, my friend and I got the first time it was explained. We just did a big section on subordinate clauses in German, which has some unique difficulties. I confess to relying on my knowledge of both Greek and English to figure out how to identify and use subordinate clauses auf Deutsch!
PS Sorry if this is a bit muddled. I am in a lot of pain because a truck hit me last week, and I can't think well.