焉 is 於之: “among them”, the two companions the sentence has just counted. 必有我師焉:

• Slingerland and Ni write exactly that: “I will always find a teacher among them”
• Watson and Chin compress it: “I’m bound to find my teacher there”
• Legge, Roberts, and Ames & Rosemont fold the pronoun into the verb, “they may serve me as my teachers”, and give the particle nothing

Whichever way it goes, the teacher is found in the company, and the 焉 is what says so.

乞, “beg”, needs someone to beg from, and the 焉 in 或乞醯焉 supplies him: 於之, “from him”.

• “from him”: Ni, Ames & Rosemont, Watson
• “of him”: Legge, Roberts
• The plain object: Lau, Chin, Slingerland, “begged him for vinegar”

Four characters on, the sentence does the same trick in the other order: 乞諸其鄰, where 諸 is 之於, “it from his neighbour”.

The one fusion 焉 in the book that all eight translators give a word: “him”. Duke Jing of Qi dies with a thousand teams of horses, and 稱, “praise”, reaches him only through the 焉: there was no virtue for the people to attach to him. Pronoun and preposition both, in English order: “praise him for” (Legge, Ni, Lau, Watson), and pronoun alone: “praise him” (Slingerland, Roberts, Ames & Rosemont, Chin).

Bo Yi and Shu Qi, in the next clause, get praised without any particle at all.

正焉 is “be corrected 於之”, by them, the people who have the Way. Three shapes in English:

• The fused pronoun kept: Slingerland “to be set straight by them”, Roberts “against their example”, Ames & Rosemont “in their company”
• The verb made reflexive, and the pronoun disappears into the learner: Ni “rectify themselves”, Watson and Chin “correct himself”
• Legge and Lau: a bare passive, “that he may be rectified”, “to be put right”

The two usages of 焉 are one word, 於 plus something, and when the something is a question, the particle comes before the verb. 仲尼焉學 is 學於誰. Legge, Slingerland, Ni, Lau, Chin write “From whom”, and Ames & Rosemont “With whom”; Roberts “Whom”; Watson “Where”.

Literally it’s closer to “where” or “how”, but Zigong’s answer is all about who, so that’s what the question was. It’s like being asked “which classroom is yours?” at school. Sure, you could say room 202, but you could just as easily say “Mrs. Krabappel’s classroom” and still have answered the question. This one passage gives you all three faces of 焉: the question here, the fusion in 莫不有文武之道焉, and a rhetorical “from whom” four characters before the end, 夫子焉不學, from whom did the Master not learn?

焉用 asks what use a thing could be:

• “Why use an ox-knife to kill a fowl?”: Legge, Slingerland, Ni, Ames & Rosemont, Watson, Chin
• Lau: “Surely you don’t need to use an ox-knife”
• Roberts: “Does one need a blade for slaughtering oxen”

The line survives as the modern proverb 殺雞焉用牛刀, with the old interrogative still in it. It’s the one place a speaker of Mandarin uses 焉 without noticing.

焉得 is “how could one get to be”, and all eight translators open the question with “how”. This is the commonest shape of the usage: 焉 right before a modal or a verb of attaining, 焉得, 焉能, asking how a thing could possibly come about.

未能事人，焉能事鬼. The question expects no answer. It’s a refusal dressed up as one. Seven of the eight write “how”, and Roberts writes “what makes you think you can serve the dead?”.

The passage repeats the frame a line later, 未知生，焉知死, where all eight write “how”.

Here the question is one of place, and all eight translators write “where”. 焉往 is 往於何, “go to where”: the same 於 that hides in the fusion word, now fused with a question instead of a pronoun.

無自辱焉, “do not bring disgrace on yourself”. The verb already has its object, 自, oneself, so there’s no room for a 之 in the 焉. Some read it as 於是, “in the attempt”, and Slingerland’s “lest you incur insult” hints at that, and Legge, Ni, and Watson give a bare prohibition: “Do not disgrace yourself”.

Compare 11.19 貨殖焉, where Legge does supply a referent, “his goods are increased by him”, and shows how easily a bleached 焉 slides back into the fusion.

名不稱焉: one’s name goes unspoken. Commentators who want an antecedent make the 焉 “in the world” or “after his death” (沒世). Ni’s “at the end of their life” goes that way, and Legge, Slingerland, Lau, and Watson simply stop at the verb.

But 沒世 is when, not where, and the clause is complete without it. This is the particle at its most bleached: a settled assertion, nothing more.

Two questions, each closed by 焉: 孰先傳焉？孰後倦焉. You can try to hear 傳焉 as “transmit it”, but the thing transmitted is 孰, the question word at the head of the clause, and it can’t be picked up again at the end. The 焉 marks the question, as 乎 or the modern 呢 would. Lau, Watson, Ni, and Legge all build the question out of “what” and let the particle go.

The clearest case in the book. 如日月之食 is already a complete comparison, the gentleman’s faults are like an eclipse, and the 焉 has no verb to attach an object to and no place to name. It closes the simile the way 然 closes 忽然. All eight translators end the sentence at “moon”. None has a word to spare for it.