missing "because"  -- (MW) The untranslated word "because" introduces a statement of fact or cause, "for what," "because," "since," and "wherefore." Jesus usually uses this word to mean "because."

The -- The word translated as "the" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

time -- "Time" is a noun that means "due measure," "season," "opportunity," "time," and "profit."

is -- (WT) This helping verb "is" indicates that the verb is passive. Helping or auxiliary verbs are needed to translate the Greek verb forms into English.  This helping verb indicates the present tense of the verb, but the tense is the past perfect.

fulfilled, -- "Fulfilled" is a verb that means "to fill," "to fulfill," and "to fill full." However, its has a very strong sense of "making" something "full" or "complete." 

and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also"). In a series, it can be translated as "not only...but also." After words implying sameness "as."

the  -- The word translated as "the" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

kingdom -- The word translated as "kingdom" can be the region, the reign, the castle or the authority of a ruler. Christ does not seem to use it to mean a physical region, so its translation as "reign" or "realm" seems more appropriate. This is especially true because the "reign" of a king means the execution of his will.

of -- This word "of"  comes from the genitive case of the following word that requires the addition of a preposition in English.  The most common is the "of" of possession.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article," the," which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," and "those"). See this article for more. MW - Missing Word -- The word "the/this" before "heaven" is not shown in the English translation.

God -- The word translated as "God" means "God" and "deity." It is introduced with an article, so "the God," "the Divine" or "the divine one." Jesus often uses it this way perhaps to indicate the one God as opposed to the pagan gods.

is -- (WT) This helping verb indicates the present tense of the verb, but the tense is the past perfect.

at hand: -- The word translated as "is at hand" is the verb form of an adverb that means "near" in space, time, and relationships. It means "to bring near," "to approach," "to bring up to," and "to be imminent." In English, we would say "nears" or, in the form here, "has neared," doesn't quite work so perhaps "has gotten close" or, in the case of time, "is nearly here." This is the same verb that is translated as "is at hand" in the phrase, "The kingdom of heaven is at hand."The verb is not seen in written Greek before Jesus and used by him only seventeen times.

repent --  (CW) The word translated as "repent" has nothing to do with sin or, generally, with religion or asking for forgiveness. The Greek word translated as "repent" has a primary meaning of understanding something after the fact, with the sense of seeing it is too late. Is specific meaning is to "understand afterward," as seeing the truth after a mistake is made. From this idea, it comes to mean to change your mind, shifting your perspective. This is in the form of a command. The "repent" does not capture the word's specific meaning.

you -- This is from the second-person, plural form of the verb.

and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also"). In a series, it can be translated as "not only...but also." After words implying sameness "as."

believe -- (CW) The Greek word translated as "believe" does not apply to religious belief as much but trusting or relying upon other people, especially their words. Jesus usually uses it in contexts, such as the one here, that apply to trusting words.

missing "in"  -- (MW) The untranslated word  "in," "within," "with" (an instrument), "by" (near), "by" (means of), "during" (time),  or "among"  with a dative object as the one here.  With the accusative, it means "into," "on," and "for." When referring to time, it means "during." It can mean "on," "at," or "by" in the sense of "near."

the  -- The word translated as "the" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

gospel. -- (CW) "Gospel" has come to mean the Jesus story itself, i.e. the Gospel, but Jesus doesn't seem to use it that way at all. This is Jesus's only used of the noun form of the word. The phrase doesn't mean the "good news itself." Instead. it means "the reward for bringing good news.