air

Compared meaning: a tune or melody (noun).

比较义项：曲调，旋律（名词）。

• air 本词

  A literary or old-fashioned word for a tune, mostly found in music or poetry today; rarely used in everyday conversation.

  一种文学化或较为陈旧的说法，指曲调，如今主要出现在音乐或诗歌语境中，日常口语中很少使用。

  The old fiddler played a haunting air passed down through generations.

  那位老提琴手演奏了一首代代相传、扣人心弦的曲子。

• tune

  The everyday, most common word for a simple musical sequence; used casually in speech, e.g. humming, whistling, or 'catchy tune'.

  日常生活中最常用的词，指简单的乐曲；用于口语中，例如哼唱、吹口哨，或『朗朗上口的曲调』。

  I can't get that catchy tune out of my head today.

  我今天满脑子都是那首朗朗上口的曲子，怎么也甩不掉。

• melody

  A more musical or literary word, often for the main, memorable line of a piece of music; suggests beauty or artistry.

  更具音乐性或文学色彩的词，常指乐曲中主要、令人难忘的旋律线，带有优美、富有艺术感的意味。

  The composer wrote a beautiful melody for the film's opening scene.

  这位作曲家为电影的开场画面创作了一段优美的旋律。

Air, tune, and melody can all mean the tune of a piece of music. Tune is the most common and casual word. Melody is more artistic or literary, often describing a beautiful, memorable musical line. Air is old-fashioned and literary, rare in daily conversation.

这三个词在此义项上都指乐曲的曲调或旋律，但语域和使用频率不同：tune 最口语化、最常用；melody 更具艺术性，常形容优美动听的旋律；air 是较陈旧、文学化的说法，日常很少使用。这里不比较 air 的『神态，样子』这一义项。

Compared meaning: to let fresh air into a space (verb).

比较义项：使通风，让新鲜空气进入（动词）。

• air 本词

  Informal, everyday word; used for freshening clothes, bedding, or a room by briefly exposing it to fresh air, often outdoors or by opening windows.

  口语化、日常用语；指通过让衣物、被褥或房间短暂接触新鲜空气来使其清新，常在户外晾晒或短暂开窗时使用。

  Hang the sheets outside to air them for an hour.

  把床单挂在外面晾一个小时透透气。

• ventilate

  More formal and technical; refers to keeping air circulating through an enclosed space such as a room or building for hygiene, safety, or removing odors and fumes; not used for clothes or bedding.

  更正式、专业；指让空气在房间或建筑物等封闭空间内持续流通，以保持卫生、安全，或排出异味和废气；不用于衣物或被褥。

  The factory must be properly ventilated to remove chemical fumes.

  这家工厂必须做好通风，以排出化学烟雾。

Air and ventilate both mean letting fresh air into a space. Air is informal, used for briefly freshening clothes, bedding, or a room by opening windows. Ventilate is more formal and technical, meaning to keep air moving through an enclosed room for hygiene or safety.

air 和 ventilate 在“使通风”这一意义上很接近，但语体不同：air 更口语化，常指把衣物、被褥或房间拿到户外或开窗透透气；ventilate 更正式，强调让封闭空间内的空气持续流通，常见于书面或技术语境。这里不比较 air 作名词表示“空气”，或作动词表示“播出（节目）”等其他意义。

Compared meaning: to broadcast a program or signal (verb).

比较义项：（电视、广播）播出，发送信号（动词）。

• air 本词

  Used for broadcasting a program at a scheduled time on TV or radio; the subject is usually the show, channel or network, not the signal itself.

  用于指电视或广播节目在预定时间播出，主语通常是节目、频道或电视台，而不是信号本身。

  The final episode airs live at nine o'clock tonight.

  大结局将于今晚九点直播播出。

• transmit

  A more technical word for sending out radio or electronic signals; the object is usually the signal itself, and no scheduled program for an audience is implied.

  是更技术性的词，指发出无线电或电子信号，宾语通常是信号本身，不一定涉及面向观众的定时节目。

  The old tower still transmits emergency signals across the valley.

  那座旧发射塔仍在向山谷各处发送紧急信号。

Air and transmit both relate to broadcasting. Air means showing a program on TV or radio at a set time; the subject is usually the show, not the signal. Transmit is more technical, meaning to send out a radio or electronic signal.

这两个词都能表示把内容或信号向外播送，但侧重不同：air强调节目按预定时段对观众播出，宾语通常是节目本身；transmit更偏技术性，强调信号被发送出去的过程，宾语通常是信号本身，也常用于与广播无关的信号传输场合。这里不比较air作名词表示“空气”的用法，也不比较transmit表示“传播（疾病等）”的其他义项。