missing "but"  -- (MW) The untranslated word "but" joins phrases in an adversarial way. Since it always falls in the second position, translating it as "however" often captures its feeling better.

To -- This word "to" comes from the dative case of the following word that requires the addition of a preposition in English. The most common is a "to" for the English indirect object. However, the translator can choose other prepositions: "with,"  "in,"   "of,"  "as," "by," "for," "at," or "on" depending on the context.

what -- The Greek word translated as "whereunto" in the singular means "anyone," "someone," and "anything." In the plural, it means "some," "they," and "those." Its use often indicates a question. It is in the form of an indirect object "to what."

can -- (WW)  This helping verb "can" indicates that the verb is the future tense. Helping or auxiliary verbs are needed to translate the Greek verb forms into English. This, however, is not the right verb.

I -- This is from the first-person, singular form of the verb.

compare - The verb translated as "compare " is a verb that means "to make like," "compare," or "to liken." It is in the future tense. 

this  - The word translated as "this" means "this," "here," or "that." This word appears after "generation" for more emphasis.

missing "the"  -- (MW) The untranslated word is the Greek definite article, 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," "those"). See this article for more. 

generation?  -  (CW) The word translated as "generation" means "race," "type," "family," and "generation." Christ uses this term frequently in criticism, but that criticism seems more aims at the human race, or, more narrowly, his own people, that it is his generation. It is the word from which we get the scientific "genus." However, more narrowly, he could also mean "this type of people." 

They --  (WN) This is from the third-person, singular form of the verb.

are - -- (WN) The verb "are" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition.  However, it is singular.

like  - "Like" is a Greek adjective meaning "like." This is the adjective form of the verb used above. 

children  - (CW) "Children" is a word that means "little one" so "little boy" and "little girl" but it is not associated with either sex. It is not the word usually translated as "children" in the New Testament. Read this article about words translated as "child" or "children" in the Gospels. 

 sitting - (WT) "Sitting" is a Greek verb that means to "be seated," "sit," especially of courts, councils, assemblies, etc. The form is an adjective, "sitting," but as an action completed in the past, "having been seated ." The sense if being put in a position of authority. The tense is past perfect. It is in the middle voice, "having seated." 

missing "themselves"-- (WV) A phrase is necessary because the form of the previous verb is a middle voice, which means that the subject is to  act  on "themselves."

in   -- The word translated as "in" means "in," "within," "with," 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. The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

marketplaces , -  "Marketplaces" is a word that means is any assemblage of people, a place where people gather, a market or a street. The idea of "sitting in an assembly" is specifically the idea of being in a position of authority. 

and --  Some versions of the Greek source used today have the Greek word "and" here in the Greek source.

missing "those"  -- (MW) The untranslated word is "those" is a demonstrative pronoun ("this" "that"), but it often acts as a pronoun ("the one that), especially a connective pronoun ("the one that") introducing a dependent clause.

calling  - (CW)  The Greek word translated as "calling"  means to "call or speak to," call by name," or "issue directions or orders." This word is also uncommon for Christ. Christ uses other terms to mean "call by name" and "speak to" so the sense of "issuing orders" is most likely and consistent with what follows. 

out -- -- (IW) There is nothing that can be translated as "out" in the Greek source.

to  -- This word "unto" comes from the dative case of the following word that requires the addition of a preposition in English. The most common is a "to" for the English indirect object. However, the translator can choose other prepositions: "with,"  "in,"   "of,"  "as," "by," "for," "at," or "on" depending on the context.

missing "the"  -- (MW) The untranslated word is the Greek definite article, 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," "those"). See this article for more. 

others --  The word translated as "others" means "one of two," "other," or "different." It is an adjective used as a noun. The sense is "the others."