阅读材料，回答下列问题。
材料一：到了明末清初，我国科技开始徘徊并趋于落后，而在西方，进入18世纪中期以后，一场以机器代替手工劳动的工业革命从英国开始，并逐渐向欧美各国扩散，人类社会的蒸汽时代和电气时代相继到来。
材料二：乾隆年间，礼部尚书沈德潜作诗咏《黑牡丹》，其中有“夺朱非正色，异种亦称王”之句，后来被告发。清廷认为，这是影射满洲人以异族夺取朱明皇位，犯大逆罪。当时，沈德潜已死，清廷下令剖棺锉尸。
材料三：清雍正皇帝反复强调“农为天下之本务，而工贾皆末也。”“市肆之中多一工作之人，即田亩之中少一耕稼之人。”
（1）请指出人类社会进入“蒸汽时代”和“电气时代”的标志各是什么？
（2）19世纪，率先完成工业革命和实现电气化的分别是哪些国家？
（3）根据材料二、三，分析明末清初，我国垂头丧气开始徘徊并逐步落后的原因。

牛顿是近代自然科学的奠基人之一，他的主要成就是（    ）

①创建微积分 ②提出相对论 ③发现万有引力定律④发现力学三定律

    Two magazines recently listed the best cities to live in. Here are two of the cities listed as "the world's best."

    SAN JOSE, COSTA RICA The city has comfortable weather all year round (15℃ to 26℃). Housing is not very expensive in San Jose. Also, many of the city's older neighborhoods are very beautiful and have small hotels and cafés. Beautiful mountains are around the city. Lots of people go sightseeing there every year. But air pollution is a problem in the city center.

    HONG KONG, CHINA This lively city—once a small fishing village—is today an international business center. It is an interesting mix of East and West, old and new. Modern tall buildings are next to small temples (庙宇). Popular nightclubs are close to traditional teahouses. Busy people fill the streets at all hours of the day. But outside the city, there are parks for walking or relaxing. Hong Kong is famous for its wonderful native dishes. There's also food from Europe, North America, and other parts of Asia. However, this small city has a large population of nearly seven million! That's why housing is often very expensive. Traffic and air pollution are also a problem.