1
turn on/off one's headlights
headlights 通常用复数形式。
He turned on his headlights as dusk fell.
黄昏时他打开了车头灯。
前灯；车头灯
先理解核心含义，再看它在真实句子里的用法。
前灯；车头灯
a bright light with a reflector, fixed to the front of a car or locomotive
He turned on his headlights as dusk fell.
黄昏时他打开了车头灯。
机动车前部带透镜和反射镜的明亮车灯,用于夜间照亮道路,通常成对。
A bright light, with a lens and reflector, on the front of a motor vehicle (or originally a ship or train), designed to illuminate the road when driving at night; normally one of a pair.
带反射器的强力灯,装在汽车或机车前部
a powerful light with reflector; attached to the front of an automobile or locomotive
I turned on the car's headlights before driving through the dark tunnel.
我开车穿过黑暗的隧道前打开了汽车的前灯。
One of the motorcycle's headlights stopped working during the night ride.
夜间骑行时，摩托车的一个前灯不亮了。
The driver cleaned the headlight so the road would be clearly visible.
司机擦干净了车头灯，以便看清路面。
headlights 通常用复数形式。
He turned on his headlights as dusk fell.
黄昏时他打开了车头灯。
这里的 on 是副词，表示“开着”的状态。
Drivers must drive with their headlights on at night.
夜间驾车必须开着前灯。
The headlights illuminated the foggy road.
车头灯照亮了雾气弥漫的道路。
Not this
The car has two headlight.
Use this
The car has two headlights.
headlight 是可数名词，表示两盏车灯时要用复数 headlights。汉语没有复数变形，容易漏掉 -s。
Not this
Please open the headlights.
Use this
Please turn on the headlights.
汉语的“开灯”的“开”在英语中对应 turn on / switch on，而 open 只表示打开门、窗等有开口的事物，不能与 headlights 搭配。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
打开车头灯
It was getting dark, so she turned on the headlights.
天黑了，所以她打开了车头灯。
汽车前灯
The car headlights lit up the dark road.
汽车前灯照亮了黑暗的道路。
前灯光束
The headlight beam cut through the fog.
前灯光束穿透了雾气。
迎面驶来的车头灯
The oncoming headlights dazzled the driver for a moment.
迎面驶来的车头灯让司机一时目眩。
明亮的车头灯
The bright headlights made it easy to see the deer on the road.
明亮的车头灯让人很容易看到路上的鹿。
吓得发愣，不知所措
When the teacher asked him the question, he froze like a deer in headlights.
老师提问时，他像被车头灯照到的鹿一样愣住了。
发短 /ɛ/ 音 (如 head, bread)
Use headlight naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
head（头）+ light（灯）→ 装在车“头”的“灯”，即车头灯。想象夜晚的车头两盏灯照亮前路，记住 headlight。
语域：neutral 常见场景：日常驾驶、车辆维修、使用手册 headlight 是中性常用词，日常会话和一般书面说明中都可以使用；正式技术文档中也比较常见，但通常没有特别口语或俚语色彩。
以上 -light 复合词（flashlight, spotlight, daylight, moonlight, sunlight, nightlight）都以 /laɪt/ 结尾，且重音模式相同（第一个词素重读，-light 次重读），可用来比较拼写与读音。注意拼写相似的词 'delight' /dɪˈlaɪt/ 重音在 -light 上，与这些复合词的 -light 并非同一重音位置；另外 headlight 的 head 读 /hɛd/，不要读成 /hiːd/。
Dictionary facts from ECDICT, WIKTIONARY.
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