Mark 2:20 But the days will come, when the bridegroom shall be taken away from them, and then shall they fast in those days.
There are going to start, however, times when he might be carried off from them, the bridegroom, and then they a going to abstain in that day.
Christ uses fasting, going without eating, and mourning the loss of someone as closely connected ideas. this is seen more clearly in the verse related to this in Matthew 9:15 (discussed here). The the physical loss of giving up food is connected with the emotional loss of losing a relationship. Happiness depends on our relationships and our physical and mental well-being. All three parts of life are closely connected.
All three parts of life are also temporary because much is hidden from us in this life. Though Christ promises to be with us on all days (Matthew 28:20), he also recognizes that he is not physically apparent (Matthew 26:11) as he is in life. To be alive is to have nothing permanently: not satisfaction from hunger or satisfaction from our relationships. Even the most perfect relationships are marked by absences.
Notice that Christ does not refer to people moving through time, but the times (in this case the "days") as moving toward us and then away from us. We are like God in the sense that we are in essence timeless and eternal, but we are placed in the path of time, in lives of temporary things: our bodies, our thoughts, and our relationships are all temporary. Our actions and choices are temporary. All of these things move, but at our core we are still, centered, unmoving. We experience life as a parade of days. It is the stream we are lost in, the water that we must be pulled from in order to wake up and turn ourselves around.
"Will come" is from a verb that means "to start", "to set out", "to arrive at", "to come" and "to go." It generally refers to any kind of motion. It is a little like we use the phrase "he is on his way," which can mean either that he is coming or going with no direct reference to coming to or going from the position of the speaker.
"Shall be taken" is means "to lead off", "to lift off", "to carry off, ""to remove", "to get rid of," and "to lead away."
ἐλεύσονται (3rd pl fut ind mid) "Will come" is from erchomai, which means "to start," "to set out", "to come", "to go," and any kind of motion. It means both "to go" on a journey and "to arrive" at a place.
δὲ (partic) "But" is from de which means "but" and "on the other hand." It is the particle that joins sentences in an adversarial way but can also be a weak connective ("and") and explanation of cause ("so") and a condition ("if").
ἡμέραι (noun pl fem nom ) "Day" is from hemera, which, as a noun, means "day" "a state or time of life", "a time (poetic)", "day break" and "day time." It is also and also has a second meaning, of "quiet", "tame (animals)", "cultivated (crops)," and "civilized (people)."
ἀπ᾽ (prep) "From" is from apo, a preposition of separation which means "from" or "away from" from when referring to place or motion, "from" or "after" when referring to time, "from" as an origin or cause. --
αὐτῶν (adj pl masc gen) "Them" is from autos, which means "the same," and the reflexive pronouns, "myself", "yourself", "himself", "herself", "itself," or the oblique case of the pronouns, "him", "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord."
καὶ (prep) "And" is kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just." -- The Greek word translated as "and" is used as the conjunction "and", but it also is used to add emphasis ("also") and, in a series, is best translated as "not only...but also." When used in writing, it creates complex sentences, but when spoken, it makes a good pausing point so that an important or humorous word can follow.
τότε (adv) "Then" is from tote, which means "at that time" and "then."
ἐκείνῃ (adj sg fem dat) "Those" is ekeinos (kakeinos), which means "the person there", "that person", "that thing", "in that case", "in that way", "at that place," and "in that manner." -- The word translated as "those" is an adjective that highlights its noun as in a specific place from a word that means "there."
τῇ ἡμέρᾳ. (noun sg fem dat) "Days" is from hemera, which, as a noun, means "day" "a state or time of life", "a time (poetic)", "day break" and "day time." It is also and also has a second meaning, of "quiet", "tame (animals)", "cultivated (crops)," and "civilized (people)."