Meaning: 'Has worked' means that something has been successful or effective in the past and has implications for the present.

Wrong options:

• stopped: 'Stopped' is in the past tense and implies a cessation of action, which contradicts the context of ongoing effectiveness.
• they relied: 'They relied' is in the past tense and suggests dependence rather than success, which does not fit the context of effectiveness.
• higher: 'Higher' is an adjective that does not fit grammatically as it does not convey an action or state of being.
• have worked: 'Have worked' is also present perfect but is plural, which does not agree with the singular subject implied in the context.

Correct answer: they reasoned

Explanation: The phrase 'they reasoned' fits grammatically as it is in the past tense, aligning with the narrative that describes policymakers' thoughts during the last wave of automation. It indicates a logical conclusion drawn by the policymakers based on the situation.

Meaning: 'They reasoned' means that they thought logically or came to a conclusion based on the information available to them.

Wrong options:

• stopped: 'Stopped' does not fit as it does not convey reasoning or thought processes.
• they relied: 'They relied' suggests dependence rather than reasoning, which does not fit the context of logical deduction.
• higher: 'Higher' is an adjective and does not fit grammatically as it does not convey an action or thought process.
• have worked: 'Have worked' is present perfect and does not fit the past context of reasoning.

Correct answer: heavily

Explanation: The adverb 'heavily' modifies the verb 'invested' and indicates the extent of the investment in education. It fits grammatically and contextually as it emphasizes the significant amount of resources allocated to education.

Meaning: 'Heavily' means to a great degree or in large amounts, indicating substantial investment.

Wrong options:

• stopped: 'Stopped' does not fit as it implies a cessation rather than an investment.
• they relied: 'They relied' does not fit grammatically as it does not modify the verb 'invested' and does not convey the extent of investment.
• higher: 'Higher' is an adjective and does not fit as it does not describe the manner of investment.
• have worked: 'Have worked' does not fit as it does not relate to the action of investing.

Correct answer: started

Explanation: The verb 'started' is in the past tense, which is appropriate as it refers to the beginning of the industrial revolution. It fits grammatically and contextually as it describes an action that occurred in the past.

Meaning: 'Started' means to have begun something, in this case, the industrial revolution.

Wrong options:

• stopped: 'Stopped' is in the past tense but implies an end rather than a beginning, which contradicts the context.
• they relied: 'They relied' does not fit as it does not convey the action of beginning and is not in the correct tense.
• higher: 'Higher' is an adjective and does not fit grammatically as it does not convey an action.
• have worked: 'Have worked' is present perfect and does not fit the past context of the industrial revolution.