First, you must understand that a subordinate clause begins its life as a complete sentence. Even as a subordinate clause, it retains its original subject-verb structure. All subordinate clauses have both a subject and a verb.
Next, you must understand that the subordinate clause gives up its identity as a complete sentence to function as only a part of some other sentence. The subordinate clause may act as a noun (in any way a noun can function), an adjective, or an adverb in this other sentence. Because it gives up its identity as a whole sentence to become merely a part of some other sentences, we say it is "subordinated."
Subordinate clauses are not unimportant; they are merely stepping down from being independent sentences to function as lesser structures.
A gerund is one of the three types of verbals. Verbals are formed from verbs and retain many characteristics of verbs, including the ability to have objects, complements, and modifiers. Verbals are used as some other part of speech, perhaps a noun or an adjective or an adverb.
Gerunds always act or function as nouns (in any way a noun can function). Gerunds are formed from the present participle form of the verb; that is, they always end in "-ing."
Gerunds, like all nouns, name things. Gerunds name actions. The purpose of a gerund in a sentence to not to provide the main action or state of being. That is the job of the verb. The gerund "names" an action or state of being, thereby acting as a noun.
TIP: Gerunds have no auxiliary (helping) verbs. Auxiliary verbs show tense. Gerunds are nouns and have no tense. When you find an "- ing" word that is formed from a verb, but has no auxiliary verbs, you know it must be either a gerund noun or a present participle adjective. The present participle form is NEVER used alone as a verb.
The objective complement is a noun or pronoun or adjective that comes after a direct object and renames or describes the direct object. Certain verbs, such as called, named, considered, elected, and thought are frequently present in sentences that have an objective complement. (This is not an exhaustive list.)
The use of an object complement prevents misunderstanding the writer's intent. Look at this sentence:
Jane called her dog.
This sentence seems to indicate that Jane summoned her dog to come to her. The use of an objective complement lets us know what Jane called her dog.
Jane called her dog Skippy.
This sentence makes it clear that Jane is not summoning her dog, but naming her dog. Objective complements make clear the intent of the sentence by renaming or describing the direct object.
A noun clause can function in a sentence in the same ways as a single-word noun can function in a sentence. Until you are able to determine how a single-word noun is used in a sentence, you will not be able to determine how an entire simple sentence can be turned into a subordinate clause to function as a single noun.
If you are having trouble determining how a noun clause is being used, review the different simple sentence patterns to increase your understanding of subjects, objects, complements, etc. Only then will noun clauses make any sense to you.
Verb tenses are used to show the time of an action or state of being. There are four primary verb tenses, each with a reference to present time, past time, and future time. The "formulas" describing the use of auxiliary verbs in these tenses are given in the Grammar Review pages.
The simple tenses are the simplest, indeed. Only the future simple tense has an auxiliary verb (helping verb), will. The simple tenses can show only basic references to time and cannot show the relationship between two actions.
The perfect tenses all have something to do with the past.
The present perfect tense shows some action that began in the past and continues to the present. I have walked to school can indicate that I just completed my trip to school or that I am familiar with walking to school or that I started this practice in the past and continue to walk to school as in the sentence, I have walked to school for six years.
The past perfect tense shows some action that began and ended in the past before some other action occurred in the past. I had completed my test before the bell rang. I started and completed an action in the past (completing my test) before some other past action occurred (the bell rang).
The future perfect tense shows some future action that begins and ends prior to some even more future action. By this time next Friday, I will have enrolled in college. Before some future time (next Friday), I will have started and completed some action (enrolling in college) that I have not yet begun (or that I have begun, but not yet completed). In other words, by this time next Friday (the future), I can look back on enrolling as a past event.
The progressive tenses show action in progress and create clearer, more immediate mental images. The simple past I walked and the past progressive I was walking both indicate the same action in the past, but was walking shows the action in progress. The same is true for the present progressive and the future progressive tenses.
The perfect progressive tenses, as suggested by the name, combine the ability to show two actions in the proper relationship to each other (perfect tenses) AND the ability to show that action in progress (progressive tenses).
Both adjective phrases and adverb phrases are prepositional phrases. If the prepositional phrase answers the questions that an adjective answers, it is called an adjective phrase. If a prepositional phrase answers the questions that an adverb answers, it is called an adverb phrase. It's just that simple.