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Complete treatment of Latin's six conditional types, from simple fact to mixed contrary-to-fact.

HSK 4 | verb / noun | expressing official or personal acceptance and endorsement

HSK 3 | verb | to flip, turn over, or browse through something

Complete N4 vocabulary list: ~700 new words at N4 level (cumulative ~1,500). Organized by category with readings, romaji, English meanings, and notes.

HSK 3 | noun | reason, grounds, justification for an action or belief

HSK 2 | verb + result complement | indicates the action of looking results in actually seeing

HSK 3 | noun | a period in history defined by distinctive features

HSK 4 | verb | to contact, to come into contact with, to touch

HSK 1 | noun | chair, seat

Complete JLPT N5 exam prep: format breakdown, 20 vocabulary practice questions, 20 grammar practice questions, 2 reading passages, listening strategies, 30-day study plan, mnemonics, and common traps.

HSK 5 | noun | a course of study; a curriculum or program of classes

Express past events in Japanese using verb, adjective, and noun past forms, and use timeline vocabulary to sequence events in time.

Exploring how classical Chinese grammar and vocabulary permeate formal Modern Chinese — 所 nominalization, 之 particle, and registers of elegance

HSK 4 | verb / noun | to respect; respect

HSK 1 | ordinal number | the ordinal prefix 第 plus one; first in a sequence

HSK 2 | verb / noun | to respond to a question; a response or answer

HSK 3 | noun / verb | development, growth; to develop, to expand

We are given several piles of worms arranged in order. The worms are numbered consecutively across all piles. If the pile sizes are: then the first pile contains worms numbered 1 through 2, the second pile contains worms numbered 3 through 9, and the third pile contains worms…

Victor wants to build a set of integers within a specified range such that the XOR of all its elements is minimized. The set can contain up to k elements, all distinct, and every element must lie between l and r inclusive.

HSK 5 | adjective | urgent; pressing; in a hurry

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

HSK 3 | grammar pattern | describes a quality that keeps intensifying over time

HSK 3 | adjective/noun | showing warmth and enthusiasm toward others or a cause

HSK 4 | noun | the reason or inner drive behind an action

HSK 6 | n | the deep root or foundation upon which something is built or sustained

HSK 5 | verb | to drive forward; to promote; to give impetus to

HSK 5 | noun | natural disaster, catastrophic natural event

The 15 most common mistakes English speakers make learning Mandarin Chinese — each with a wrong example, correct example, and explanation of why it matters.

N1 grammar pattern 〜だに: a literary/formal emphatic particle meaning 'even' — used to intensify a minimal or extreme case.

Full 文言文 literacy and engagement with classical Chinese literature, poetry, and the 骈文 tradition.

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

小 (small): 3 strokes, JLPT N5. On: ショウ. Kun: ちい-さい、お、こ.

気 (ki/ke/): spirit. JLPT N5 kanji.

HSK 4 | verb / noun | to research or study something; a research study

HSK 5 | noun | supply chain; the network of suppliers, manufacturers, and distributors

HSK 3 | adjective | positive, proactive, enthusiastic, optimistic

HSK 4 | noun | crisis, critical situation

HSK 3 | adverb | intensifier meaning to a very high degree

We are given an essay, which is a sequence of words, and a dictionary of synonym pairs. Each synonym pair allows us to replace one word with another, but only in the direction specified. Fedor wants to modify his essay to minimize the number of letters R (case-insensitive).

HSK 3 | noun | a paper container for sending letters

HSK 3 | noun | season — one of the four seasons of the year

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

HSK 5 | noun / verb | systematic change to improve a system or institution

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

We are given an array of distinct integers. The task is to determine whether the entire array can become sorted in increasing order after reversing exactly one contiguous segment. If it is possible, we must print "yes" and one valid segment [l, r] whose reversal sorts the array.

HSK 3 | adverb / verb | comparatively, relatively; to compare two things

雨 (rain): 8 strokes, JLPT N5. On: ウ. Kun: あめ、あま.

HSK 1 | adjective, adverb | fast, quick, quickly, soon

We start with a collection of axis-aligned segments. Every segment is either horizontal or vertical, and segments of the same orientation never overlap. We are allowed to delete whole segments or only parts of them.

明 (mei/myou/aka-rui): bright. JLPT N5 kanji.

HSK 5 | discourse marker | in summary; in short; to sum up

HSK 4 | verb/noun | physical exercise or training to improve health

HSK 5 | noun/adjective/verb | corruption; corrupt; to decay, rot

Complete JLPT N1 kanji reference: 1,000+ new kanji beyond N2, covering rare readings, similar-looking pairs, classical kanji, compound analysis, and the most important 500 N1 kanji in full detail.

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

HSK 5 | verb | to establish; to found; to set up

HSK 6 | verb | to sum up the essential points; to state in broad terms

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

HSK 3 | verb | to raise something upward or to give an example

HSK 3 | adverb | indicating original state or a surprising discovery

Learn the vocabulary, structures, and conventions of formal written Esperanto for letters, reports, and official contexts.

HSK 1 | verb | to enter, to go into, to come in

HSK 3 | adjective / noun | truthful, not deceiving; the quality of being honest

六 (roku/mut-tsu): six. JLPT N5 kanji.

Learn to talk about getting around using 怎么去 and 坐 + vehicle, and navigate common travel situations.

HSK 1 | phrase | confirms a factual statement; equivalent to 'yes, that is correct'

HSK 1 | noun | book

HSK 5 | discourse marker | it is learned that; reportedly; used to introduce information from an unspecified source

HSK 5 | noun/adjective | the central, most essential part of something

HSK 4 | adjective | pessimistic; pessimism

HSK 3 | verb | to accept, to receive, to take in willingly

HSK 3 | noun | police officer, policeman, the police

Complete reference for the 100 most important four-character idioms (四字熟語) for JLPT N1: readings, literal meanings, actual meanings, usage examples, and exam notes.

Express precise numerical and degree-based comparisons using A是B的N倍, A比B+V得多, and 差不多 at B1 level.

HSK 1 | noun | a calendar day; also the word for the sun (formal/written)

HSK 3 | noun | purpose, goal, aim, objective

HSK 2 | adjective / noun | describes physical or mental well-being

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

HSK 2 | adverb | marks the welcome or long-awaited end of a process

HSK 5 | verb/adjective | to mislead someone or to be in a state of confusion

HSK 1 | adverb | negates past actions and the verb 有

Engage with Chinese scientific discourse, technology journalism, and research communication using specialized vocabulary and evidence-based grammar patterns.

HSK 5 | verb / noun | to publish (a book or periodical)

HSK 5 | noun/adjective | a state of worry and unease; anxiety

HSK 4 | verb/noun | a face-to-face evaluation or job interview

HSK 6 | verb/adj | to concentrate meaning into few words; dense and profound in expression

四 (shi/yot-tsu): four. JLPT N5 kanji.

HSK 3 | noun | the monetary value of a product or service

HSK 5 | noun | nature reserve; protected area; conservation zone

The final two Sindarin mutations: liquid mutation (after certain prefixes ending in -r) and stop mutation (after d/t) — with scholarly discussion on their limited attestation.

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.

HSK 5 | verb/noun | to feel grateful; deep gratitude and appreciation

HSK 3 | grammar pattern | describes how well or intensely an action is performed

HSK 5 | verb / noun | to raise capital; the act of financing

HSK 5 | noun | medicine, drug, pharmaceutical substance

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

HSK 3 | noun | the degree of skill or quality in something

HSK 4 | n | the governing body of a state or region