1
speed up
speed up 也可作为及物动词短语，但不及物用法更常见。
The driver sped up when he saw the green light.
司机看到绿灯时加速了。
快速移动；疾行
sped — past of speed · irregular form
先理解核心含义，再看它在真实句子里的用法。
快速移动；疾行
To move or go quickly.
The driver sped up when he saw the green light.
司机看到绿灯时加速了。
快速移动。
To go fast.
超过限速。
To exceed the speed limit.
提高某事发生的速率。
To increase the rate at which something occurs.
使加快；迅速发送；全速行驶；因而,催促；匆忙。
To cause to make haste; to dispatch with celerity; to drive at full speed; hence, to hasten; to hurry.
speed
Base
原形
speeds
3rd person
第三人称单数
speeding
-ing
现在分词
sped
Past
过去式
speeded
Past participle
过去分词
He speeds along the highway.
他在高速公路上超速行驶。
She sped past me without stopping.
她没停就飞驰而过。
They have speeded up the process.
他们加快了进程。
注意：过去式sped，过去分词speeded。
The cyclist sped down the hill without using the brakes.
骑车人没有刹车就快速冲下山坡。
We got a ticket because we were speeding on the highway.
我们因为在高速公路上超速行驶而收到了一张罚单。
Opening the windows speeds the drying of the paint.
打开窗户能加快油漆变干。
speed up 也可作为及物动词短语，但不及物用法更常见。
The driver sped up when he saw the green light.
司机看到绿灯时加速了。
表示快速完成某事，后接名词或代词。
She speeded through her homework to catch the show.
她飞快地做完作业赶着看节目。
及物用法，较正式，常与表示目的地或接受者的词连用。
The company sped the package to the customer overnight.
公司连夜将包裹快速送达客户。
Not this
You need to speed the car.
Use this
You need to speed up the car.
动词 speed 作“加速”解时通常需要与 up 连用，构成短语动词 speed up。单独使用 speed 作为及物动词表示“使加速”不符合英语习惯，因此加上 up 使表达更自然。
Not this
He speed to work yesterday.
Use this
He sped to work yesterday.
动词 speed 的过去式是不规则的 sped，而不是 speed。英语中不规则动词的过去式需要特别记忆，不能按规则加 -ed。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
加速；加快
The company hired more workers to speed up production.
公司雇佣更多工人来加快生产。
飞驰而过
A fire engine sped past our house.
一辆消防车从我们家门口飞驰而过。
快速完成
He sped through his breakfast and left.
他匆匆吃完早饭就离开了。
疾驰而去
She got in the car and sped off.
她上车后疾驰而去。
沿……快速行驶
The boat sped along the coast.
小船沿着海岸快速行驶。
加速；加快
The new software will speed up the process.
新软件将加快这一过程。
（时间）飞逝
The weekend sped by.
周末一晃就过去了。
飞驰而去
She sped off in her car.
她开车飞驰而去。
速度从来没有杀死过任何人。突然静止不动，那才会要你的命。
The car sped along the road.
汽车沿着道路飞驰。
我想知道音速。
The train sped through the tunnel.
火车飞速穿过隧道。
发长 /iː/ 音 (如 see, free)
Use sped naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
记忆：speed 发音像一阵风呼啸而过，开快车超速就是它；sped 是过去式，更短更快。
语域：mixed 常见场景：daily conversation、traffic/road、formal writing speed 作动词时，不同义项的语域差别较大：表示“快速移动”或“超速行驶”时在日常生活中和交通场景里很常见，比较自然；表示“加快、促进”时多用于较正式或书面表达。实际使用需根据具体义项和场合选择，不宜一概而论。
作为动词时，既可作及物动词（如speed the process），也可作不及物动词（如speed along）。常与up连用形成短语动词，表示‘加速’。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.