extension
extension — adjective
- extensionpositive
- more extensioncomparative
- most extensionsuperlative
1. describes additional schoolwork or activities designed to push students beyond t
describes additional schoolwork or activities designed to push students beyond their basic tasks by introducing harder or more varied challenges.
The teacher gave the faster students an extension task on ancient Rome.
extension + noun (task) for students who finish early
Renata enjoyed the extension activities in her maths class because they made her think more deeply.
Extension work is often provided for pupils who have already mastered the main lesson.
Brian chose an extension project about robotics instead of the standard homework.
- advanced
implies higher difficulty level; less emphasis on enrichment
- basic
fundamental level without extra challenge
文法句型
extension + noun (course, work, activity)
用法筆記
Only used before a noun (e.g. extension course, extension work). Nearly always in educational contexts, particularly British schools.
常見錯誤
2. relating to university courses that are open to members of the public who are no
relating to university courses that are open to members of the public who are not working toward a degree.
The university extension program offers evening classes in art history for local residents.
extension program + offers + noun phrase
Tara signed up for an extension course in creative writing at the city college.
Many extension students are working adults who study in their spare time.
Extension departments often arrange lectures that are free and open to everyone.
- continuing education
broader term; includes professional development, not just university outreach
文法句型
extension + noun (course, program, department)
用法筆記
Frequently appears with 'department', 'program', 'course', or 'student'. Distinguished from sense 1 by involving university outreach rather than in-school enrichment.
extension — noun
- extensionsingular
- extensionsplural
1. the act or fact of making something larger, longer, or more far‑reaching — for e
the act or fact of making something larger, longer, or more far‑reaching — for example, extending a deadline, a visa, or the scope of an argument.
The government granted a three-month extension on the visa application deadline.
granted + extension + on + noun phrase (deadline)
Ari asked his professor for an extension on the term paper because he was ill.
The extension of the motorway will connect the two cities by 2027.
The charity announced the extension of its free meal programme to cover two more neighbourhoods.
The red carpet was an extension of the stage, leading right into the audience.
- expansion
implies growth in size or scale rather than length
- lengthening
specifically about making something longer physically
- prolongation
formal; specifically about extending time
- shortening
making something shorter in length or duration
- contraction
reduction in size or scope
文法句型
extension of + noun
extension to + noun
on extension
用法筆記
Can be countable (a short extension, three extensions) or uncountable when referring to the general process. The phrase 'by extension' is a fixed adverbial expression used to logically broaden an argument.
常見錯誤
2. a separate phone in a building that shares one outside line with other units but
a separate phone in a building that shares one outside line with other units but can be reached by dialling its own internal code.
Please dial 0 and then the extension number 342 to reach the sales team.
dial + extension + number pattern
Talia picked up the phone and asked the receptionist to put her through to extension 219.
Every desk in the office has its own extension so colleagues can call each other directly.
Wei called the hotel and asked to be connected to Mr. Chen's room extension.
文法句型
extension + number
dial + extension
用法筆記
Often followed by a number (extension 219). In offices, each employee typically has a personal extension linked through a switchboard.
常見錯誤
3. a short code, typically a dot followed by three or four letters, that is placed
a short code, typically a dot followed by three or four letters, that is placed after a file's name and tells the computer what kind of data the file contains, so the right software can open it.
Images with the .jpg extension can be opened by most photo editing programs.
.jpg extension — common image file type
Reuben could not open the file because his computer did not recognise the .docx extension.
You can change the file extension to .pdf if you want to share the document more easily.
Sade renamed the video file but kept the .mp4 extension so it would still play.
文法句型
file extension + .xxx
filename + extension
用法筆記
Common extensions include .pdf, .docx, .jpg, .png, .mp4, .exe. Changing a file extension without converting the file format can make the file unreadable.
常見錯誤
4. real or artificial strands that you attach to your existing hair, giving it extr
real or artificial strands that you attach to your existing hair, giving it extra length or volume.
Imani bought clip-in hair extensions for the wedding to make her ponytail look fuller.
clip-in hair extensions — type + purpose
The salon offers tape-in extensions that last about eight weeks before they need adjusting.
Ziad's sister had her hair extensions removed because the weight was hurting her scalp.
Good-quality extensions can be washed and styled just like natural hair.
- hair pieces
broader term; can include wigs and toppers, not just lengthening additions
文法句型
wear + extensions
get + extensions
hair + extensions
用法筆記
Almost always used in the plural ('extensions') when referring to the hair pieces themselves. Common attachment methods include clip-in, tape-in, sew-in, and fusion.
常見錯誤
5. an extra room or section added to an existing building, increasing its usable sp
an extra room or section added to an existing building, increasing its usable space.
The family built a two-storey extension at the back of their house to create a bigger kitchen.
built + extension + at the back of + house — location pattern
Felipe applied for planning permission to add a glass extension to his restaurant.
The hospital's new extension will provide space for an additional fifty patient beds.
Renata's extension cost more than expected because the builders found problems with the old wall.
- demolition
complete removal of a structure
文法句型
build + an extension
extension to + building
extension on + house
用法筆記
Often used with a prepositional phrase ('extension to the house', 'extension on the school'). In British English, 'extension' typically refers to a structure added to a building, not a separate building.
常見錯誤
6. a movement in which you straighten a joint such as the elbow or knee, often perf
a movement in which you straighten a joint such as the elbow or knee, often performed as an exercise to strengthen or stretch the muscles.
The physiotherapist told Tara to do three sets of ten leg extensions every morning.
do + [number] + leg extensions — countable exercise sets
Tricep extensions help strengthen the back of the upper arm when done with weights.
Knee extensions are often prescribed after surgery to rebuild muscle control.
Brian felt a burn in his thighs after twenty leg extensions at the gym.
- straightening
everyday word for the movement; less technical
- flexion
the opposite movement — bending a joint
文法句型
do + extensions
leg extension
arm extension
用法筆記
Often appears in compound forms: 'leg extension', 'tricep extension', 'knee extension'. Frequently used in physiotherapy and weight-training contexts.
7. a department within a higher education institution that runs courses for local c
a department within a higher education institution that runs courses for local community members who are not working toward a degree.
The university extension offers affordable evening classes in languages and the arts.
university extension + offers + noun phrase — typical subject-verb-object
Wei enrolled in a photography course through the local university extension.
Extension programmes at public universities are often subsidised to keep fees low.
Élise completed a certificate in business management from the university extension.
- continuing education
broader category that includes professional development and adult learning
文法句型
extension + of + university
university + extension
用法筆記
Distinguish from adjective sense 2: as a noun, 'extension' (uncountable) refers to the programme itself, while the adjective form modifies a following noun ('extension course').