Detailed Instructions: You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").
Q: Paragraph- Sent 1: Into the 21st Century: As 1997 drew nearer, it became clear that the Chinese government had no intention of renewing the 99-year lease on the New Territories.
Sent 2: Negotiations began, and in 1984 Prime Minister Margaret Thatcher signed the Sino-British Joint Declaration, in which Britain confirmed the transfer of the New Territories and all of Hong Kong to China in 1997.
Sent 3: For its part, China declared Hong Kong a “Special Administrative Region” and guaranteed its civil and social system for at least 50 years after 1997.
Sent 4: Although China’s Basic Law promised that Hong Kong’s existing laws and civil liberties would be upheld, refugees began flowing the other way.
Sent 5: The British Nationality Act (1981) had in effect prevented Hong Kong citizens from acquiring British citizenship, and thousands of people, anxious about their future under China’s rule, were prompted to apply for citizenship elsewhere, notably in Canada and Australia.
Sent 6: The protests in 1989 in Beijing’s Tiananmen Square sparked sympathy marches in Hong Kong, and further increased tension with China.
Sent 7: Some companies moved their headquarters out of Hong Kong.
Sent 8: Ironically, as the handover approached, the British granted the Hong Kong Chinese more political autonomy than they had done since the colony was founded, including such democratic reforms as elections to the Legislative Council.
Sent 9: Since the handover in July 1997, China has generally followed a hands-off policy.
Sent 10: Many who fled have returned.
Sent 11: What controls heartbeats in Hong Kong are the fluctuations of the Hang Seng Index, foreign currency exchange rates, and skyrocketing property prices.
Sent 12: In short, the status quo prevails.
Sent 13: Everybody hopes Hong Kong will remain stable, but everyone also has their doubts.
Sent 14: In the meantime, the philosophy is to seize present-day opportunities in the thriving economy. 
Question: Why did companies move their headquarters out of Hong Kong?.
A:
6, 7.