Narrated lessons
Videos
Full lesson videos with English narration and English + Chinese subtitles.
One video per syllabus topicEnglish + 中文 subtitlesChapters, so you can jump
1465 lessons 158 hours of video
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Most watched
18:08
The CPU
The processor in your phone is doing something almost stupidly simple. Fetch one instruction. Work out what it means. Do it. Then fetch the next one. That is…
30:48
Number
Two buses leave the same stop at nine o'clock. One runs every twelve minutes, the other every eighteen. When do they next leave together? Not at thirty…
21:16
Why Computers Use Binary
Inside a processor there are billions of tiny switches. Each one can only be on, or off. That is all a computer physically has — no threes, no sevens, no…
13:11
Hardware & Software
Here is a brand new computer. Every physical part works — the processor, the memory, the screen, the keyboard. Switch it on, and nothing happens. No desktop…
17:50
Understanding business activity
Look at any high street. Shop after shop, all selling something, all chasing the same customers. Every one of them is a business. But what is a business really…
15:03
Chemical Bonding
Two molecules, almost the same size. Water, and hydrogen sulfide. Sulfur sits directly below oxygen in the Periodic Table, so you would expect the two to…
Tips
Every video walks through one syllabus topic from the start: the idea, the working, and the exam-style examples — narrated in clear English, at the level the notes are written for.
Subtitles are burned in, in English and Simplified Chinese together, so a difficult sentence can be read while it is heard. Difficult terms carry a small Chinese gloss on screen.
Each video is chaptered. Use the chapter list to jump to the part you need, and the notes and lessons linked beside it to practise afterwards.
IGCSE
A2 Key and B1 Preliminary (KET, PET) · Cambridge English · A2 Key (KET)
7 video lessons
0.5 hours of video
A2 Key and B1 Preliminary (KET, PET) · Cambridge English · B1 Preliminary (PET)
8 video lessons
0.5 hours of video
ACT
28 video lessons
3.5 hours of video
AQA · GCSE · Chemistry
10 video lessons
1.8 hours of video
AQA · GCSE · Mathematics
6 video lessons
0.5 hours of video
AQA · GCSE · Physics
7 video lessons
2.6 hours of video
Biology
7 video lessons
5.1 hours of video
Chinese Foundations
6 video lessons
0.3 hours of video
Economics
8 video lessons
0.7 hours of video
English A1
16 video lessons
1.2 hours of video
English A2
15 video lessons
1.0 hours of video
English B1
14 video lessons
0.9 hours of video
English B2
14 video lessons
0.9 hours of video
GRE General Test
15 video lessons
0.6 hours of video
GRE Subject Test · GRE Mathematics
31 video lessons
1.5 hours of video
GRE Subject Test · GRE Physics
47 video lessons
4.6 hours of video
GRE Subject Test · GRE Psychology
26 video lessons
1.7 hours of video
HSK 1
9 video lessons
0.4 hours of video
HSK 2
7 video lessons
0.3 hours of video
HSK 3
8 video lessons
0.5 hours of video
HSK 4
31 video lessons
1.6 hours of video
HSK 5
45 video lessons
2.6 hours of video
HSK 6
31 video lessons
1.8 hours of video
IELTS Academic
5 video lessons
2.0 hours of video
IGCSE Biology
21 video lessons
3.0 hours of video
IGCSE Business Studies
6 video lessons
1.2 hours of video
IGCSE Chemistry
12 video lessons
2.6 hours of video
IGCSE Computer Science
10 video lessons
2.1 hours of video
IGCSE Economics
6 video lessons
1.2 hours of video
IGCSE English
11 video lessons
1.4 hours of video
IGCSE Mathematics
9 video lessons
1.9 hours of video
IGCSE Physics
6 video lessons
2.0 hours of video
International Baccalaureate · IB Diploma · Biology · HL
31 video lessons
2.1 hours of video
International Baccalaureate · IB Diploma · Biology · SL
27 video lessons
1.8 hours of video
International Baccalaureate · IB Diploma · Business Management · HL
6 video lessons
0.6 hours of video
International Baccalaureate · IB Diploma · Business Management · SL
5 video lessons
0.5 hours of video
International Baccalaureate · IB Diploma · Chemistry · HL
12 video lessons
0.8 hours of video
International Baccalaureate · IB Diploma · Chemistry · SL
11 video lessons
0.7 hours of video
International Baccalaureate · IB Diploma · Classical Languages · HL
4 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Classical Languages · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Computer Science · HL
8 video lessons
0.7 hours of video
International Baccalaureate · IB Diploma · Computer Science · SL
7 video lessons
0.6 hours of video
International Baccalaureate · IB Diploma · Creativity, Activity, Service
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Dance · HL
4 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Dance · SL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Design Technology · HL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Design Technology · SL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Digital Society · HL
4 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Digital Society · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Economics · HL
6 video lessons
0.9 hours of video
International Baccalaureate · IB Diploma · Economics · SL
5 video lessons
0.7 hours of video
International Baccalaureate · IB Diploma · Environmental Systems and Societies · HL
11 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Environmental Systems and Societies · SL
8 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Extended Essay
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Film · HL
4 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Film · SL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Geography · HL
4 video lessons
0.5 hours of video
International Baccalaureate · IB Diploma · Geography · SL
3 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · Global Politics · HL
4 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · Global Politics · SL
3 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · History · HL
4 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · History · SL
3 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Language A: Language and Literature · HL
4 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Language A: Language and Literature · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Language A: Literature · HL
4 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Language A: Literature · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Language B · HL
4 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · Language B · SL
3 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Language ab initio · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Literature and Performance · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Mathematics: Analysis and Approaches · HL
6 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · Mathematics: Analysis and Approaches · SL
6 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Mathematics: Applications and Interpretation · HL
6 video lessons
0.4 hours of video
International Baccalaureate · IB Diploma · Mathematics: Applications and Interpretation · SL
6 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Music · HL
4 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Music · SL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Philosophy · HL
4 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Philosophy · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Physics · HL
23 video lessons
1.6 hours of video
International Baccalaureate · IB Diploma · Physics · SL
18 video lessons
1.2 hours of video
International Baccalaureate · IB Diploma · Psychology · HL
4 video lessons
0.6 hours of video
International Baccalaureate · IB Diploma · Psychology · SL
3 video lessons
0.5 hours of video
International Baccalaureate · IB Diploma · Religion and Society · SL
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Social and Cultural Anthropology · HL
4 video lessons
0.3 hours of video
International Baccalaureate · IB Diploma · Social and Cultural Anthropology · SL
3 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Sports, Exercise and Health Science · HL
7 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Sports, Exercise and Health Science · SL
7 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Theatre · HL
4 video lessons
0.2 hours of video
International Baccalaureate · IB Diploma · Theatre · SL
3 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Theory of Knowledge
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Visual Arts · HL
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · Visual Arts · SL
1 video lessons
0.1 hours of video
International Baccalaureate · IB Diploma · World Religions · SL
1 video lessons
0.1 hours of video
OxfordAQA · International GCSE · Mathematics
4 video lessons
0.3 hours of video
OxfordAQA · International GCSE · Physics
8 video lessons
0.7 hours of video
Pearson Edexcel · International A-Level · Biology
4 video lessons
0.6 hours of video
Pearson Edexcel · International A-Level · Chemistry
4 video lessons
1.6 hours of video
Pearson Edexcel · International A-Level · Further Mathematics
10 video lessons
1.0 hours of video
Pearson Edexcel · International A-Level · Mathematics
9 video lessons
0.7 hours of video
Pearson Edexcel · International A-Level · Physics
6 video lessons
1.8 hours of video
Pearson Edexcel · International A-Level · Pure Mathematics
7 video lessons
0.7 hours of video
Pearson Edexcel · International GCSE · Economics
7 video lessons
0.5 hours of video
Pearson Edexcel · International GCSE · Mathematics A
6 video lessons
0.5 hours of video
SAT
29 video lessons
1.9 hours of video
TOEFL iBT
5 video lessons
1.4 hours of video
A-Level
A-Level Biology
19 video lessons
3.3 hours of video
A-Level Business
10 video lessons
1.9 hours of video
A-Level Chemistry
37 video lessons
5.5 hours of video
A-Level Computer Science
20 video lessons
5.7 hours of video
A-Level Economics
12 video lessons
2.6 hours of video
A-Level Further Mathematics
4 video lessons
0.7 hours of video
A-Level Mathematics
6 video lessons
1.5 hours of video
A-Level Physics
25 video lessons
6.6 hours of video
AP
AP 2-D Art and Design
6 video lessons
0.8 hours of video
AP Biology
8 video lessons
1.1 hours of video
AP Calculus AB
8 video lessons
1.2 hours of video
AP Calculus BC
10 video lessons
1.6 hours of video
AP Chemistry
9 video lessons
1.3 hours of video
AP Computer Science A
4 video lessons
0.7 hours of video
AP Computer Science Principles
5 video lessons
0.7 hours of video
AP Cybersecurity
4 video lessons
0.6 hours of video
AP Drawing
7 video lessons
0.9 hours of video
AP English Language and Composition
9 video lessons
0.9 hours of video
AP English Literature and Composition
9 video lessons
1.3 hours of video
AP Environmental Science
9 video lessons
1.3 hours of video
AP European History
9 video lessons
1.3 hours of video
AP Human Geography
7 video lessons
1.0 hours of video
AP Macroeconomics
6 video lessons
0.8 hours of video
AP Microeconomics
6 video lessons
0.9 hours of video
AP Physics 1
8 video lessons
1.1 hours of video
AP Physics 2
7 video lessons
1.0 hours of video
AP Physics C: Electricity and Magnetism
6 video lessons
1.0 hours of video
AP Physics C: Mechanics
7 video lessons
0.9 hours of video
AP Precalculus
4 video lessons
0.8 hours of video
AP Psychology
5 video lessons
1.1 hours of video
AP Statistics
9 video lessons
1.2 hours of video
AP United States History
9 video lessons
1.2 hours of video
AP World History: Modern
9 video lessons
1.1 hours of video
GAC
GAC Academic English
6 video lessons
2.0 hours of video
GAC Business
3 video lessons
1.2 hours of video
GAC Computing
3 video lessons
1.1 hours of video
GAC Mathematics
4 video lessons
1.1 hours of video
GAC Psychology
2 video lessons
0.7 hours of video
GAC Science
2 video lessons
0.8 hours of video
GAC Social Science
2 video lessons
0.7 hours of video
GAC Study and Communication Skills
5 video lessons
0.8 hours of video
Coding courses
C Programming
23 video lessons
0.9 hours of video
Code Pseudocode
14 video lessons
0.5 hours of video
Cyber security
16 video lessons
0.5 hours of video
Databases & SQL
17 video lessons
0.6 hours of video
Java for AP CS A
16 video lessons
0.5 hours of video
JavaScript
15 video lessons
0.6 hours of video
LaTeX
14 video lessons
0.5 hours of video
Linux & the command line
12 video lessons
0.4 hours of video
Python Basics
15 video lessons
0.8 hours of video
Python for A-Level CS
15 video lessons
0.6 hours of video
Python for AP CS Principles
14 video lessons
0.5 hours of video
Python for IGCSE CS
14 video lessons
0.5 hours of video
Web Basics — HTML & CSS
19 video lessons
0.7 hours of video