The character comparator.

Self vs. already: the opening at the bottom is the whole difference (巳, the snake, completes the trio).

Person vs. enter: the strokes diverge at the top.

Not yet vs. end: the horizontal lengths swap the meaning.

Earth vs. scholar: which stroke is longer decides it.

Sun vs. eye: one inner line changes everything.

Great vs. too: the dot under 大.

Tree vs. root: the baseline marks the origin.

Pull out vs. dial: the hand radical is shared; the right side differs by one stroke.

Clear (weather) vs. eyeball: sun vs. eye radical.

Drink vs. thirsty: mouth radical vs. water.

Blue vs. basket: grass head vs. bamboo head.

Buy vs. sell: the seller adds a mark on top (买/卖).

Ask vs. hear/smell: mouth vs. ear inside the gate (问/闻).

Resemble vs. elephant: the person radical marks the abstract sense.

Wine vs. sprinkle: water radical plus a near-identical right side.

Argue / distinguish / braid: speech, knife, silk between 辛 (辩辨辫).

de ×3: possessive, complement, adverbial; same sound, different grammar.

zài at/in vs. zài again: existence vs. repetition.

zuò do/make vs. zuò work/act: concrete vs. abstract "do".

zuò to sit vs. zuò seat/measure: verb vs. noun.

huì learned skill vs. néng capability: both "can".

háishi "or" in questions, huòzhě "or" in statements.

To know of vs. to comprehend: 了解 is acquaintance, 理解 is grasp.

Two ways to say "two": counting vs. measuring.

Wear (through the body) vs. wear (on the surface).

zhùyì pay attention vs. zhǔyi an idea: tone flip, different word.

Know a fact vs. know a person: 知道 facts, 认识 acquaintances.

Feel/sensation (noun-ish) vs. feel/think (opinion).

Time/wait 候 carries a slim 亻 stripe down the middle; feudal-lord 侯 drops it, 时候 vs 王侯.

Dense 密 caps 山 with a roof (thick as hills); honey 蜜 caps 虫, the bee underneath.

History 历 hides 力 under the cliff; severe 厉 hides 万, 经历 vs 厉害.

Garden 园 walls in 元; round 圆 walls in 员, same enclosure, different yard (公园 vs 圆圈).

Tool 具 vs all 俱, the person radical collects everyone: 家具 vs 面面俱到.

Ledger 账 carries cowrie-money 贝; tent 帐 carries cloth 巾, 记账 vs 帐篷.

Both "again": 又 replays what already happened (他又迟到了), 再 schedules what has not (这件事明天再谈).

Same slot, opposite expectation: 就 says "earlier/faster than expected" (我马上就来), 才 "later than expected" (他九点才起床).

对 is the everyday "toward" and doubles as "correct" (你说得对); 对于 is the formal, written "regarding" that only fronts a topic (对于我来说没任何意义).

有点 + adjective = "somewhat", usually a complaint (有点累了); 一点 measures a noun or degree — in negatives, "not the least bit" (一点关系都没有).

帮助 carries its object directly (帮助别人); 帮忙 splits — the helped person goes inside (帮我的忙), or it stays whole (谢谢你帮忙).

以后 anchors "after" to a point, future included (穿好衣服以后); 后来 is "later on" in a past story and stands alone (但后来忘了).

Both drop in as "suddenly" adverbs (我忽然想起); only 突然 also works as an adjective — 很突然 is fine, 很忽然 is not.

一直 is one unbroken stretch (我一直在等你); 总是 is every single time — a habit on repeat (她总是忘记带钥匙).

满意 = pleased with something (对他的新车很满意); 满足 = fulfill a need or feel content inside (满足您的要求).

适合 is the verb — it takes an object (中号更适合您); 合适 is the adjective "suitable" — no object allowed (对我正合适).

通过 goes through a method — "by means of" (通过他的介绍); 经过 goes through a place or a span of time (刚从这里经过).

Same fǎnyìng: 反应 is the response to a stimulus (做出反应); 反映 is the mirror that shows what lies underneath (反映了它的文化).

Same bìxū: 必须 is the adverb "must" before a verb (必须去医院); 必需 is "essential" and sticks to nouns (必需品).

为了 aims forward at a goal — "in order to" (为了感谢您); 因为 points back at a cause — "because" (因为下雨，比赛取消了).

所以 draws the logical conclusion (很冷，所以我不想出去); 于是 narrates the next move — "thereupon" (于是出现了一个问题).

知道 = have the fact (他知道这件事); 明白 = grasp the meaning — "got it" (我明白了，谢谢你).

Same "other": 别的 is the spoken default (别的地方); 其他 is the formal, written "the rest" (其他更好的事情).

经验 is banked know-how (工作的经验); 经历 is what you lived through — and the verb "to undergo" (经历了很多变化).

发生 = happen — events do it themselves (这种事发生了); 发现 = discover — you notice what was already there (发现读这本书很难).

收到 puts a concrete thing in your hands (收到了朋友的一封信); 接受 takes on the abstract — a job, advice, criticism (接受这份工作).

借 is free — borrow or lend (借你的笔记); 租 costs money — rent by the day or the month (租车).

刚 is an adverb welded to the verb (刚回到家); 刚才 is a time noun — it can open the sentence on its own (刚才桌子上有一本书吗？).

常常 = often, raw frequency, future included (常常迟到); 往往 = a pattern read off experience — "more often than not", past and present only (往往没有很多顾客).

本来 = originally, the plan before reality (我本来应该读一下这本书); 原来 can mean "originally" too, but only it delivers the "aha, I see" discovery (原来如此).

认为 states a considered opinion (我认为你知道那不是真的); 以为 voices a supposition — usually a mistaken one (你真的以为我会帮你吗？).

把 hauls the object up front so the subject can dispose of it (不要把我们的计划告诉任何人); 被 marks the subject as the one taking the hit (被爱).

终于 lands the long-awaited result — "at last" (他终于完成了他的目标); 到底 presses for the bottom line and sharpens questions (到底是什么).

已经 = "already" — done as of now (已经做完了); 曾经 = "once" — an experience that is over (曾经住过的房子).

次 counts occurrences — how many times it happened (去过三次北京); 遍 counts complete run-throughs — the whole thing, start to finish (再说一遍).

和 is the spoken "and" between equal nouns (喝茶和咖啡); 以及 is the written "as well as" that chains longer lists (农业信息以及农产品技术).

渡 adds 氵 to 度 — crossings that feel like water (渡河, 过渡); bare 度 measures degree (温度) and spends time (度假).

Same sound shell 喿: fire 火 makes 燥 the dry one (干燥); foot 足 makes 躁 the fidgety one (急躁, 烦躁).

Mirror-image meals: 即 kneels toward the food — "about to / even if" (即将, 即使); 既 turns away, meal done — "already / since" (既然).