Unit 5 covers 1750 to 1900, and it has two engines running at once: an intellectual revolution that changed how people justified political authority, and an industrial revolution that changed how societies produced and lived. Most questions ask you to connect them.

Enlightenment 启蒙运动 philosophies applied new ways of understanding and empirical approaches 实证方法 to both the natural world and human relationships. From that came ideas that questioned established traditions:

• Individualism 个人主义, natural rights 天赋权利, and the social contract 社会契约.
• Calls for religious tolerance 宗教宽容 and limits on established authority.

Those ideas influenced reform movements 改革运动: the expansion of suffrage, the abolition of slavery, and demands for women's suffrage 妇女选举权诉求 alongside an emergent feminism 女权主义 that challenged political and gender hierarchies.

Nationalism 民族主义 became a major force shaping historical developments. People developed a new sense of commonality 共同体意识 based on language, religion, social customs, and territory, and these newly imagined national communities were often linked to state-building.

Discontent with monarchist and imperial rule encouraged revolution 革命. Enlightenment ideas, as reflected in revolutionary documents, justified those movements, and colonial subjects in the Americas led a series of rebellions inspired by them - the examinable set being the American, French, Haitian, and Latin American revolutions.

The pattern to hold: an idea (rights, consent, nation) plus a grievance (taxation, exclusion, slavery, colonial rule) produces a movement. Answers that give only the idea, or only the grievance, explain nothing.

A variety of factors contributed to the growth of industrial production: access to coal 煤炭 and iron 铁, navigable rivers and canals, agricultural productivity 农业生产率 that freed labour, capital 资本 and legal protection for it, urbanisation, and access to raw materials and markets through overseas empire.

The factory system 工厂制度 concentrated production in a single location under supervision, replacing dispersed household production. That change - as much organisational as technical - is what made the scale of output possible.

The rapid development of steam-powered 蒸汽动力 industrial production in Europe spread to other regions, and as new methods became common, states that industrialised gained enormous advantages in wealth and military power over those that did not.

Technology compounded the change: the steam engine 蒸汽机 and later the internal combustion engine 内燃机; the second industrial revolution 第二次工业革命 in steel, chemicals, and electricity; and railroads 铁路, steamships 蒸汽船, and the telegraph 电报, which made exploration, colonisation, and administration at a distance possible.

As industrial influence grew, a small number of states sponsored industrialisation 国家推动工业化 directly - the standard examples being Meiji Japan, Russia under state-led programmes, and Egypt under Muhammad Ali.

Western European countries began abandoning mercantilism and adopting free trade 自由贸易 policies, and the global nature of trade and production contributed to the proliferation of transnational businesses 跨国企业 and new financial instruments.

Reaction came from several directions:

• Workers organised, often in labour unions 工会, and pressed for shorter hours, safety, and wages.
• Alternative visions of society emerged - socialism 社会主义, communism 共产主义, and anarchism 无政府主义 - as critiques of industrial capitalism.
• Some governments passed reform legislation 改革立法 on working conditions, child labour, and public health.
• The expansion of industrialising states led to internal reform movements 内部改革运动 elsewhere in Asia, as states tried to respond to new pressure.

New social classes 社会阶级 formed, including a middle class 中产阶级 and an industrial working class 工业工人阶级, each with its own culture and politics.

Other changes are examinable: rapid urbanisation 城市化 with overcrowding and disease; changes in family structure 家庭结构 and in women's work as production left the home; and rising standards of living 生活水平 over the long run, unevenly distributed and reached only after decades of hardship.

The unit's reasoning skill is continuity and change. Production and class structure changed fundamentally, while imperial competition, coerced labour in colonised regions, and inequality persisted in new forms.

Worked example (a real AP exam question). AP World short-answer questions here ask, for example, to "Explain one way in which industrialisation changed social structures" between 1750 and 1900. A full-mark answer names the change and traces it: "Industrialisation created a large industrial working class, because the factory system concentrated production in single locations and drew rural labourers into cities to work for wages, replacing household production and the rural social order that depended on it." Notice the shape: explain requires the mechanism - factory system, urban migration, wage labour - not just the statement that new classes appeared.

• Answer "why Britain first" with several factors at once - coal, capital, agriculture, empire - not one cause.
• The factory system is an organisational change; say what it replaced.
• For revolutions, pair an idea with a grievance. Either alone explains nothing.
• State-sponsored industrialisation (Meiji Japan, Russia, Egypt) is the contrast to the British pattern.
• Give the reactions as a set: unions, socialism and communism, and reform legislation.
• Living standards rose eventually and unevenly. Saying so is what makes an answer an evaluation.