brain

tamnd's digital brain — notes, problems, research

42088 notes

认识 (rènshi) — to know (a person), to recognize

HSK 3 | verb | to be acquainted with someone; to recognize or identify

hsk-3vocabularya2
Japanese Study Roadmap

Week-by-week Japanese study plan from absolute beginner to JLPT N1: phased milestones, resource recommendations, and time estimates.

japanesemethodologyroadmapstudy-planjlptlanguage-learning
它 (tā) — it

HSK 1 | pronoun | third-person singular pronoun for non-human things

hsk-1vocabularya1
新 — JLPT N5 Kanji

新 (shin/atara-shii): new. JLPT N5 kanji.

japanesekanjin5jlpt
债券 (zhàiquàn) — bond; debenture

HSK 5 | noun | bond; debenture; fixed-income debt security

hsk-5vocabularyb2
哭 (kū) — to cry

HSK 3 | verb | to cry; to weep; to shed tears

hsk-3vocabularya2
即便 (jíbiàn) — even if

HSK 5 | conjunction | even if, even though

hsk-5vocabularyb2
篇 (piān) — piece of writing; article (measure word)

HSK 2 | measure word | counts complete pieces of written or composed work

hsk-2vocabularya1
程序 (chéngxù) — program, procedure

HSK 4 | noun | a set of steps or instructions; a computer program

hsk-4vocabularyb1
总结 (zǒngjié) — to summarize; summary

HSK 4 | verb/noun | to draw together key points into a conclusion

hsk-4vocabularyb1
形式 (xíngshì) — form; format; formality

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

hsk-4vocabularyb1
毕业 (bìyè) — to graduate; graduation

HSK 4 | verb / noun | to complete a course of study and graduate

hsk-4vocabularyb1
Lesson 11: Body and Basic Health

Learn body part vocabulary, how to describe symptoms using 疼 and 痛, and how to soften descriptions with 有点儿.

hsk-1lessona1
态度 (tàidu) — attitude

HSK 4 | noun | one's mental or emotional stance toward something

hsk-4vocabularyb1
你们 (nǐmen) — you (plural)

HSK 1 | pronoun | second-person plural pronoun

hsk-1vocabularya1
帅 (shuài) — handsome

HSK 1 | adjective | handsome, cool, good-looking (usually men)

hsk-1vocabularya1
协商 (xiéshāng) — to negotiate, to consult

HSK 5 | verb/noun | to discuss and reach agreement through mutual consultation

hsk-5vocabularyb2
论证 (lùnzhèng) — to argue; argumentation

HSK 5 | verb / noun | to demonstrate through argument; logical proof

hsk-5vocabularyb2
体现 (tǐxiàn) — embodiment; to embody

HSK 6 | n/v | concrete manifestation; to give concrete expression to an abstract quality

hsk-6vocabularyc1
〜とはいえ — JLPT N1 Grammar

N1 grammar pattern 〜とはいえ: acknowledging a stated fact while introducing a contrasting reality — 'even though, that said, granted that.'

japanesegrammarn1jlpt
理论 (lǐlùn) — theory

HSK 5 | noun | systematic body of ideas explaining phenomena

hsk-5vocabularyb2
Lesson 6: Literature & Arts

Develop the vocabulary and analytical grammar to discuss Chinese literary works, artistic movements, and aesthetic criticism at the B2 level.

hsk-5lessonb2
监督机制 (jiāndū jīzhì) — oversight mechanism; supervisory mechanism

HSK 5 | noun | a formal system for supervising and ensuring accountability

hsk-5vocabularyb2
先 — Kanji Reference

先 (before, ahead): 6 strokes, JLPT N5. On: セン. Kun: さき.

japanesekanjin5writing
原则 (yuánzé) — principle; rule; tenet

HSK 4 | noun | a fundamental belief or rule guiding behavior

hsk-4vocabularyb1
结婚 (jiéhūn) — to marry; to get married

HSK 3 | verb | to enter into marriage

hsk-3vocabularya2
当时 (dāngshí) — at that time; then; at the time

HSK 4 | adverb / noun | referring to a specific past moment

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
好的 (hǎo de) — okay; all right; sure

HSK 1 | greeting phrase | affirms agreement or acknowledges a request

hsk-1vocabularya1
股票 (gǔpiào) — stock; share

HSK 5 | noun | stock, share, equity security traded on a stock market

hsk-5vocabularyb2
Lesson 9: Economic Analysis

The language of Chinese economic analysis — 就...而言 in economic framing, macroeconomic and microeconomic vocabulary, and the discourse of policy economics

hsk-6lessonc1
金 — Kanji Reference

金 (gold, money): 8 strokes, JLPT N5. On: キン、コン. Kun: かね、かな.

japanesekanjin5writing
机场 (jīchǎng) — airport

HSK 3 | noun | a facility where aircraft take off and land

hsk-3vocabularya2
〜わけではない — JLPT N2 Grammar

Learn 〜わけではない to express partial negation — it doesn't mean that X, clearing up misunderstandings while allowing for nuance.

japanesegrammarn2jlpt
收集 (shōují) — Collect

HSK 4 | verb | to collect, to gather

hsk-4vocabularyb1
Lesson 7: Time, Days, and Months

Learn to tell the time, name days of the week and months, and use temporal adverbs and the correlative -am series.

esperantoa1lesson
〜だに (even / just — literary minimum marker)

N1 grammar: classical particle だに expressing literary 'even just X' or 'even merely X.' Marks the minimum case on a scale of unexpectedness. Used in literary prose and formal writing.

japanesen1grammarjlptだにclassical Japanese
N4 Kanji: 勉 (Make Effort, Study Hard)

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

japanesen4jlptkanjilanguage-learning
区块链 (qūkuài liàn) — blockchain

HSK 5 | noun | a distributed digital ledger technology for recording transactions securely

hsk-5vocabularyb2
热情 (rèqíng) — warm, enthusiastic, passionate

HSK 2 | adjective/noun | warm-hearted, enthusiastic, passion

hsk-2vocabularya1
公平 (gōngpíng) — fair, equitable

HSK 5 | adjective/noun | treating all parties equally without bias or favoritism

hsk-5vocabularyb2
蔬菜 (shūcài) — vegetables

HSK 3 | noun | vegetables, the specific category of edible plants

hsk-3vocabularya2
完善 (wánshàn) — to improve; to perfect; perfect; complete

HSK 4 | verb / adjective | bringing something to a higher or complete standard

hsk-4vocabularyb1
找到 (zhǎo dào) — to find; to successfully locate

HSK 2 | verb + result complement | indicates searching resulted in actually finding something

hsk-2vocabularya1
半导体制造 (bàndǎotǐ zhìzào) — semiconductor fabrication

HSK 8 | noun | semiconductor fabrication; the process of manufacturing integrated circuits and chips

hsk-8vocabularyc2
通过 (tōngguò) — through; by means of; to pass

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

hsk-4vocabularyb1
HSK 1 Vocabulary (299 Words)

Complete HSK 1 vocabulary list: 299 words with Chinese, pinyin, English, part of speech, and example sentences. Organized by category.

chinesehsk1vocabularybeginnerhsk
CF 472F - Design Tutorial: Change the Goal

We are given two arrays of integers, x and y, each of length n. The array x is the starting state, and y is the desired target state. The only operation allowed is x[i] ^= x[j], which replaces x[i] with the bitwise XOR of x[i] and x[j].

codeforcescompetitive-programmingconstructive-algorithmsmathmatrices
JLPT N3 Lesson 8: Workplace and Formal Japanese

Master formal request forms, business vocabulary, and the foundations of keigo (honorific language) for N3-level workplace communication: emails, phone calls, meetings, and the 丁寧語/尊敬語/謙譲語 distinction.

japanesen3lessonjlptgrammarkeigobusinessworkplace
到 (dào) — to arrive; to (a destination)

HSK 1 | verb / complement marker | indicates arriving at a destination or successful completion of an action

hsk-1vocabularya1
Lesson 14: Prefixes

Sindarin word-building with prefixes: directional, negative, intensifying, and stative prefixes with 40+ examples from attested names.

sindarinvocabularyprefixesintermediate
接受 (jiēshòu) — to accept; to receive; to take

HSK 4 | verb | to willingly take or agree to something offered

hsk-4vocabularyb1
CF 459C - Pashmak and Buses

We need to assign each student to one of k buses on each of d days. For every student, we can think of their assignment as a sequence of length d. For example, if d = 3, a student might ride buses (2, 1, 2) over the three days.

codeforcescompetitive-programmingcombinatoricsconstructive-algorithmsmath
综述 (zōngshù) — to synthesize; review article

HSK 6 | verb/noun | to synthesize existing research; a comprehensive literature review

hsk-6vocabularyc1
然而 (rán'ér) — however; but; nevertheless

HSK 4 | conjunction | a formal connector meaning however or nevertheless

hsk-4vocabularyb1
内在 (nèizài) — intrinsic, internal

HSK 5 | adjective | existing within something, inherent and not externally imposed

hsk-5vocabularyb2
曾经 (céngjīng) — once / at one time

HSK 3 | adverb | once, at one time, formerly — always refers to past experience

hsk-3vocabularya2
韧性 (rènxìng) — resilience

HSK 5 | noun | the ability to recover from adversity and adapt to challenges

hsk-5vocabularyb2
Lesson 12: B2 Review and Path to C1

Consolidate all B2 grammar and vocabulary, assess your current competency level, identify common B2 errors, and plan your pathway to C1.

esperantob2lesson
三 (sān) — three

HSK 1 | number | the digit three

hsk-1vocabularya1
大方 (dàfang) — generous; natural and poised

HSK 3 | adjective | freely giving; composed and graceful in manner

hsk-3vocabularya2
差不多 (chàbuduō) — almost; about the same

HSK 3 | adjective/adverb | nearly equal or approximately

hsk-3vocabularya2
Lesson 18: Participles — Active and Passive

All four Latin participles (PAP, PPP, FAP, gerundive), their formation and declension, and the ablative absolute construction with worked examples.

latinnovicelesson
往 (wǎng) — toward / in the direction of

HSK 3 | preposition | toward, in the direction of — indicates direction of movement

hsk-3vocabularya2
有名 (yǒumíng) — famous; well-known; celebrated

HSK 3 | adjective | widely recognized; renowned

hsk-3vocabularya2
爬 (pá) — to climb

HSK 3 | verb | to climb, to crawl, to scramble up

hsk-3vocabularya2
听到 (tīng dào) — to hear; to catch (a sound)

HSK 2 | verb + result complement | indicates the action of listening results in actually hearing

hsk-2vocabularya1
Work and Business Vocabulary

Japanese work and business vocabulary: professions, office settings, keigo expressions, job hunting terms, and workplace culture.

japanesevocabularyworkbusinessjlpt-n3language-learning
CF 460E - Roland and Rose

Roland wants to place n watch towers on a 2D integer grid around a rose at the origin so that the sum of squared distances between all pairs of towers is maximized. Each tower must lie within or on a circle of radius r centered at (0,0).

codeforcescompetitive-programmingbrute-forcegeometrymathsortings
网络 (wǎngluò) — network; online

HSK 5 | noun/adjective | network; the internet; online

hsk-5vocabularyb2
激进的 (jījìn de) — radical

HSK 5 | adjective | advocating extreme or rapid change; radical

hsk-5vocabularyb2
これ / それ / あれ / どれ — Demonstrative Pronouns
japanesegrammarn5demonstratives
方法 (fāngfǎ) — method; way; approach

HSK 4 | noun | a method or way of doing something

hsk-4vocabularyb1
Lesson 13: 4th and 5th Declension Nouns

Full paradigms for 4th-declension masculine and neuter nouns and 5th-declension nouns, with key vocabulary and the special behavior of domus.

latinnovicelesson
振奋 (zhènfèn) — to invigorate; inspiring; uplifting

HSK 5 | verb/adjective | to inspire; to invigorate; filled with excitement and spirit

hsk-5vocabularyb2
HSK 2.0 vs HSK 3.0 Comparison

Side-by-side comparison of HSK old standard (2.0, 6 levels) and new standard (3.0, 9 levels), including vocabulary counts, CEFR alignment, and transition timeline.

chinesehskhsk-3.0cefr
Lesson 19: Technology Ethics

Engage with Chinese discourse on the ethical dimensions of technology, including AI ethics, privacy, data security, and algorithmic bias.

hsk-5lessonb2
帮助 (bāngzhù) — to help; help

HSK 4 | verb / noun | to help; assistance

hsk-4vocabularyb1
倡议 (chàngyì) — initiative; proposal; to propose

HSK 5 | noun/verb | initiative; proposal; to put forward a proposal or call to action

hsk-5vocabularyb2
〜と — And; With (Accompaniment)
japanesegrammarn5particles
只有 (zhǐyǒu) — only if / only when

HSK 3 | conjunction | only if, only when — used in 只有...才... pattern

hsk-3vocabularya2
辩论 (biànlùn) — to debate; a debate

HSK 5 | verb / noun | to argue opposing sides; formal debate

hsk-5vocabularyb2
怎么 (zěnme) — how, why

HSK 1 | adverb/pronoun | interrogative asking about manner or reason

hsk-1vocabularya1
同意 (tóngyì) — to agree

HSK 3 | verb | to agree, to consent, to approve

hsk-3vocabularya2
需要 (xūyào) — to need

HSK 3 | verb / noun | to need, require; a need or requirement

hsk-3vocabularya2
JLPT N4 — Structured Lessons

10 structured lessons for JLPT N4: from reviewing N5 basics to complex grammar, passive/causative, conditionals, and practical reading/writing. Each lesson includes dialogues and exercises.

japanesejlptjlpt-n4lessonslanguage-learning
書 — JLPT N5 Kanji

書 (sho/ka-ku): write. JLPT N5 kanji.

japanesekanjin5jlpt
一直 (yīzhí) — all along

HSK 3 | adverb | continuously, all along, straight — describes uninterrupted action or direction

hsk-3vocabularya2
血压 (xuèyā) — blood pressure

HSK 4 | noun | the pressure of blood circulating in the arteries

hsk-4vocabularyb1
突然 (tūrán) — suddenly; all of a sudden

HSK 3 | adverb/adjective | happening without warning

hsk-3vocabularya2
JLPT N5 Lesson 5: Existence and Location

Learn to express where things and people exist using あります and います, with the に and で particles for location.

japanesen5jlptlessonlanguage-learning
集成电路 (jíchéng diànlù) — integrated circuit

HSK 8 | noun | integrated circuit; a set of electronic circuits on a single chip of semiconductor material

hsk-8vocabularyc2
宁可 (nìngkě) — would rather; prefer to

HSK 4 | adverb | expressing a preference for one option over another

hsk-4vocabularyb1
说清楚 (shuō qīngchǔ) — say clearly / explain clearly

HSK 3 | verb + result complement | to express something in a way that is fully understood

hsk-3vocabularya2
赶 (gǎn) — to rush; to catch (transport)

HSK 3 | verb | to hurry toward something or catch a vehicle in time

hsk-3vocabularya2
同事 (tóngshì) — Colleague

HSK 4 | noun | colleague, coworker

hsk-4vocabularyb1
投入 (tóurù) — to invest; to put into; input; absorbed

HSK 5 | verb/noun/adjective | to put in effort or resources; input; deeply absorbed

hsk-5vocabularyb2
密码 (mìmǎ) — password, code

HSK 4 | noun | a secret word or number used for authentication or encryption

hsk-4vocabularyb1
工作 (gōngzuò) — work; to work

HSK 1 | noun/verb | employment, labor; to be employed or carry out a task

hsk-1vocabularya1
论点 (lùndiǎn) — argument, thesis

HSK 6 | n | a main claim or point of argument in reasoning or debate

hsk-6vocabularyc1