brain

tamnd's digital brain — notes, problems, research

41905 notes

不 (bù / bú) — not, no (negation)

HSK 1 | adverb | negates verbs and adjectives for present, future, or habitual

hsk-1vocabularya1
时候 (shíhou) — time, moment, occasion

HSK 2 | noun | a point in time, a moment, an occasion (contrast with 时间)

hsk-2vocabularya1
Lesson 17: City Life

Discuss urban living, infrastructure, and city development using 在 + city + 生活/工作 and city vocabulary at B1 level.

hsk-4lessonb1
女 (nǚ) — female, woman

HSK 2 | adjective / noun | female gender; a woman or girl

hsk-2vocabularya1
医生 (yīshēng) — doctor

HSK 1 | noun | doctor, physician

hsk-1vocabularya1
根据 (gēnjù) — according to; based on; basis

HSK 4 | preposition / noun | using something as a foundation or source

hsk-4vocabularyb1
例如 (lìrú) — For example / such as

HSK 4 | adverb / conjunction | introducing an example or illustration

hsk-4vocabularyb1
万 (wàn) — ten thousand

HSK 1 | number | ten thousand; the base large-number unit in Chinese counting

hsk-1vocabularya1
相比之下 (xiāng bǐ zhī xià) — by comparison; in comparison

HSK 5 | phrase | a fixed expression introducing a comparative contrast

hsk-5vocabularyb2
CF 467C - George and Job

George wants to maximize his earnings by choosing segments of work from a list of tasks, each with a given profit. The tasks are arranged sequentially in an array p of length n. He must select exactly k non-overlapping segments, each of length m.

codeforcescompetitive-programmingdpimplementation
今 — Kanji Reference

今 (now): 4 strokes, JLPT N5. On: コン、キン. Kun: いま.

japanesekanjin5writing
体现 (tǐxiàn) — to embody; to reflect

HSK 5 | verb / noun | to embody; to give expression to

hsk-5vocabularyb2
奖学金 (jiǎngxuéjīn) — scholarship

HSK 5 | noun | financial award given to support a student's education

hsk-5vocabularyb2
入 — Kanji Reference

入 (enter): 2 strokes, JLPT N5. On: ニュウ. Kun: い-る、い-れる、はい-る.

japanesekanjin5writing
智能手机 (zhìnéng shǒujī) — smartphone

HSK 4 | noun | a mobile phone with advanced computing capabilities

hsk-4vocabularyb1
N4 Kanji: 医 (Medicine, Doctor)

JLPT N4 kanji 医 — readings, vocabulary, stroke order, mnemonic, and common confusion pairs.

japanesen4jlptkanjilanguage-learning
何 — Kanji Reference

何 (what): 7 strokes, JLPT N5. On: カ. Kun: なに、なん.

japanesekanjin5writing
理论 (lǐlùn) — theory; in theory

HSK 4 | noun | a theory or theoretical framework

hsk-4vocabularyb1
教室 (jiàoshì) — classroom

HSK 1 | noun | classroom

hsk-1vocabularya1
推进 (tuījìn) — to advance, to push forward

HSK 5 | verb | to drive progress or move something forward systematically

hsk-5vocabularyb2
平台 (píngtái) — platform; stage

HSK 4 | noun | a raised surface or an opportunity base for activity

hsk-4vocabularyb1
看 (kàn) — to look at; to watch; to read

HSK 1 | verb | seeing or viewing in multiple senses

hsk-1vocabularya1
努力 (nǔlì) — work hard; diligent; effort

HSK 2 | verb / adjective / noun | describes hard work and determined striving

hsk-2vocabularya1
计划 (jìhuà) — plan / to plan

HSK 4 | noun / verb | plan; to plan; to intend

hsk-4vocabularyb1
形象 (xíngxiàng) — image; figure; vivid

HSK 5 | noun/adjective | a person or organization's public image; also vivid/concrete representation

hsk-5vocabularyb2
哪里 (nǎlǐ) — where

HSK 1 | pronoun | interrogative pronoun for location (standard/southern form)

hsk-1vocabularya1
勤奋 (qínfèn) — Diligent

HSK 4 | adjective | diligent, hardworking

hsk-4vocabularyb1
JLPT N2 Lesson 1: Written Japanese vs Spoken

Master the fundamental stylistic differences between formal written prose and casual spoken Japanese required for N2 proficiency.

japanesen2lessonjlpt
差不多 (chàbuduō) — almost; about the same

HSK 3 | adjective/adverb | nearly equal or approximately

hsk-3vocabularya2
面对 (miànduì) — to face / to confront

HSK 4 | verb | to face; to confront; to deal with

hsk-4vocabularyb1
件 (jiàn) — measure word for clothing and matters

HSK 1 | measure word | classifier for garments and affairs

hsk-1vocabularya1
预计 (yùjì) — to expect; to estimate; to anticipate

HSK 4 | verb | to estimate or anticipate a future outcome

hsk-4vocabularyb1
自信 (zìxìn) — confident / confidence

HSK 4 | adjective / noun | confident; self-confident; confidence

hsk-4vocabularyb1
关 (guān) — to close / to turn off

HSK 1 | verb | to close, to shut, to turn off

hsk-1vocabularya1
公民 (gōngmín) — citizen

HSK 4 | n | a legally recognized member of a state

hsk-4vocabularyb1
联系 (liánxì) — to contact; to get in touch; connection

HSK 4 | verb / noun | establishing or maintaining a link between people or things

hsk-4vocabularyb1
〜すら / 〜でさえ (even — register distinction)

N1 grammar: comparing the literary particle 〜すら with the more neutral 〜でさえ and casual 〜でも for 'even.' Register hierarchy, emphatic force, and the unique 〜さえ〜ば conditional.

japanesen1grammarjlptすらでさえevenregister
质量 (zhìliàng) — quality

HSK 4 | noun | quality; standard; mass (physics)

hsk-4vocabularyb1
公共汽车 (gōnggòng qìchē) — bus

HSK 1 | noun | public bus

hsk-1vocabularya1
Lesson 7: Plurals Part 2

Advanced Sindarin plural patterns: monosyllables, diphthong shifts, vowel intrusion, class plurals (-ath, -rim, -hoth), and the definite article with plurals.

sindaringrammarpluralsintermediate
CF 449B - Jzzhu and Cities

We are given an undirected weighted graph representing cities and roads. City 1 is the capital. In addition to normal roads, there are special train routes that connect the capital directly to some city. The government wants to close as many train routes as possible.

codeforcescompetitive-programminggraphsgreedyshortest-paths
CF 479E - Riding in a Lift

We are given a line of floors from 1 to n. We start on floor a and we will make exactly k moves. Each move picks a new floor y different from the current floor x, but with a restriction: we are not allowed to move “too far” in absolute distance compared to a forbidden floor…

codeforcescompetitive-programmingcombinatoricsdp
传媒 (chuánméi) — media; mass media

HSK 5 | noun | media; mass media; communications industry

hsk-5vocabularyb2
黒 — JLPT N5 Kanji

黒 (koku/kuro): black. JLPT N5 kanji.

japanesekanjin5jlpt
車 — JLPT N5 Kanji

車 (sha/kuruma): vehicle. JLPT N5 kanji.

japanesekanjin5jlpt
记住 (jì zhù) — to remember / memorize

HSK 3 | verb | to remember something firmly; to commit to memory

hsk-3vocabularya2
累 (lèi) — tired

HSK 1 | adjective | tired, fatigued, exhausted

hsk-1vocabularya1
她们 (tāmen) — they, them (all female)

HSK 1 | pronoun | third-person plural pronoun (all-female group)

hsk-1vocabularya1
制度 (zhìdù) — system, institution, rules

HSK 5 | noun | established rules, regulations, or institutional arrangements

hsk-5vocabularyb2
建议 (jiànyì) — to suggest; suggestion; recommendation

HSK 4 | verb/noun | to propose a course of action; a recommendation offered to others

hsk-4vocabularyb1
根本 (gēnběn) — fundamental, root; fundamentally, at all

HSK 5 | adjective / adverb / noun | basic and essential; at the most basic level; not at all (negative)

hsk-5vocabularyb2
给 (gěi) — to give; for (someone)

HSK 1 | verb / preposition | means to give or indicates the recipient of an action

hsk-1vocabularya1
CF 461C - Appleman and a Sheet of Paper

We have a one-dimensional sheet of paper represented as an array of width n. Appleman can fold the sheet at a position p, which means the left segment [0, p) flips and lies over the right segment [p, currentwidth).

codeforcescompetitive-programmingdata-structuresimplementation
晩 — JLPT N5 Kanji

晩 (ban/): evening. JLPT N5 kanji.

japanesekanjin5jlpt
JLPT N5 — Vocabulary (All ~800 Words)

Complete JLPT N5 vocabulary list with ~800 words organized by category: nouns, verbs (with て-form and た-form), adjectives, adverbs, particles, question words, and expressions.

japanesejlptjlpt-n5vocabularylanguage-learning
JLPT N1 — Vocabulary

Complete JLPT N1 vocabulary reference: ~4,000 new words beyond N2 covering academic, literary, political, legal, medical, and financial Japanese with readings, meanings, and usage contexts.

japanesejlptjlpt-n1vocabularylanguage-learning
现代 (xiàndài) — modern; contemporary

HSK 3 | adjective/noun | relating to the present era

hsk-3vocabularya2
Sindarin Nouns

Sindarin nouns: i-affection plural formation, the definite article, direct object marking, and the genitive construction.

sindaringrammarnounstolkien
Lesson 4: Direction Complements

Learn how direction complements combine with verbs to describe movement toward or away from the speaker, a key feature of Mandarin spatial expression.

hsk-3lessona2
Lesson 5: Eating & Drinking

Sindarin vocabulary for food, drink, and dining — with attested and Neo-Sindarin words, plus basic sentence construction practice.

sindarinvocabularyfoodbeginner
通过 (tōngguò) — through; by means of; to pass

HSK 4 | preposition / verb | passing through or using a method

hsk-4vocabularyb1
相对 (xiāngduì) — relatively; relative; mutual

HSK 5 | adjective/adverb | indicating something is not absolute but comparative or relational

hsk-5vocabularyb2
快乐 (kuàilè) — happy, joyful

HSK 2 | adjective | a feeling of happiness and joy

hsk-2vocabularya1
Lesson 21: Advanced Grammar — Formal Patterns

Classical-influenced formal patterns in modern Chinese — 以...之名, 为所欲为, 无论如何, and the grammar of extreme and universal quantification

hsk-6lessonc1
唱 (chàng) — to sing

HSK 1 | verb | to sing

hsk-1vocabularya1
竞争力 (jìngzhēnglì) — competitiveness

HSK 4 | noun | the ability or capacity to compete effectively

hsk-4vocabularyb1
可以 (kěyǐ) — can, may (permission or possibility)

HSK 2 | modal verb | expressing permission or general possibility; contrast with 能 for ability

hsk-2vocabularya1
三 (sān) — three

HSK 1 | number | the digit three

hsk-1vocabularya1
没必要 (méi bìyào) — no need / unnecessary

HSK 4 | phrase | there is no need; it is unnecessary

hsk-4vocabularyb1
特定 (tèdìng) — specific; particular; designated

HSK 4 | adjective | referring to a specific, pre-determined thing rather than a general one

hsk-4vocabularyb1
Lesson 17: Verbs — Present Tense

Complete Sindarin verb conjugation for present tense: aorist (simple) and continuative (ongoing) for both A-stem and primary verb classes, all 6 persons.

sindaringrammarverbspresent-tenseintermediate
〜を通じて — JLPT N2 Grammar

Learn how to use 〜を通じて (wo tsujite) to express 'through,' 'throughout,' or 'via' when describing a medium, channel, or continuous span. Includes structure, nuance, examples, and comparisons.

japanesegrammarn2jlpt
历程 (lìchéng) — course; journey; process

HSK 4 | noun | the process or journey through which something develops

hsk-4vocabularyb1
双 (shuāng) — pair; both; double (measure word)

HSK 2 | measure word / adjective | counts items that come in pairs

hsk-2vocabularya1
增长 (zēngzhǎng) — to grow, growth (in quantity)

HSK 5 | verb/noun | quantitative increase or growth in numbers

hsk-5vocabularyb2
あります / います — Existence of Things and Beings
japanesegrammarn5existence
对 (duì) — correct / towards

HSK 1 | adjective / preposition | correct, right; directed at, towards

hsk-1vocabularya1
Lesson 2: Numbers 0-100

Master Chinese numbers, measure words, and how to ask quantities with 几 and 多少.

hsk-1lessona1
宪法 (xiànfǎ) — constitution

HSK 5 | noun | the supreme law of a country that defines government structure and rights

hsk-5vocabularyb2
说明 (shuōmíng) — to explain; explanation; manual

HSK 4 | verb/noun | to clarify or describe something; a written explanation or instruction manual

hsk-4vocabularyb1
時 — JLPT N5 Kanji

時 (ji/toki): time. JLPT N5 kanji.

japanesekanjin5jlpt
前 — Kanji Reference

前 (before, front): 9 strokes, JLPT N5. On: ゼン. Kun: まえ.

japanesekanjin5writing
错误 (cuòwù) — mistake / wrong

HSK 4 | noun / adjective | mistake; error; wrong; incorrect

hsk-4vocabularyb1
書 — Kanji Reference

書 (write): 10 strokes, JLPT N5. On: ショ. Kun: か-く.

japanesekanjin5writing
Sindarin Dictionaries

All Sindarin dictionaries compared — Parf Edhellen, Eldamo, Hiswelókë — with guidance on when to use each and how to interpret source period labels.

sindarindictionariestolkienvocabulary
〜に先立って — JLPT N2 Grammar

Learn how to use 〜に先立って (ni sakidatte) to express 'prior to' or 'before' when an action precedes an important event. Includes structure, nuance, examples, and comparisons.

japanesegrammarn2jlpt
云计算 (yún jìsuàn) — cloud computing

HSK 5 | noun | cloud computing; internet-based computing services

hsk-5vocabularyb2
教授 (jiàoshòu) — Professor

HSK 4 | noun/verb | professor; to teach, to instruct

hsk-4vocabularyb1
それから (それから) — Japanese Vocabulary

それから (それから / sorekara): and then, after that. N4 level Japanese vocabulary.

japanesevocabularyn4conj
开创 (kāichuàng) — to pioneer; to create; to open up

HSK 5 | verb | to be the first to establish or bring something into existence

hsk-5vocabularyb2
Lesson 6: Translation Studies

Advanced theory and practice of translation into and from Esperanto — literary, technical, and cultural dimensions, with the translator's full toolkit.

esperantoc1lesson
形式 (xíngshì) — form; format; formality

HSK 4 | noun | the outward shape, structure, or format of something

hsk-4vocabularyb1
N4 Kanji: 者 (Person (by occupation))

JLPT N4 kanji 者 — readings, vocabulary, stroke order, mnemonic, and common confusion pairs.

japanesen4jlptkanjilanguage-learning
英 — JLPT N5 Kanji

英 (ei/): England. JLPT N5 kanji.

japanesekanjin5jlpt
邀请 (yāoqǐng) — to invite / invitation

HSK 4 | verb / noun | to invite; an invitation

hsk-4vocabularyb1
输 (shū) — to lose (a competition)

HSK 3 | verb | to lose a game, match, or contest

hsk-3vocabularya2
主观 (zhǔguān) — subjective

HSK 5 | adjective/noun | subjective; based on personal feelings rather than facts

hsk-5vocabularyb2
促进 (cùjìn) — to promote; to advance

HSK 5 | verb | to promote; to facilitate; to further

hsk-5vocabularyb2
Sindarin Vocabulary: People and Races

Sindarin words for people, races, relationships, titles, and names for individuals.

sindarinvocabularypeopleracestolkien
中间 (zhōngjiān) — middle; between; among

HSK 3 | noun / preposition | the space or position in the middle of something

hsk-3vocabularya2